diff --git a/cascade-2.2.0-nomanual.patch b/cascade-2.2.0-nomanual.patch
deleted file mode 100644
index 0c5064f95b3..00000000000
--- a/cascade-2.2.0-nomanual.patch
+++ /dev/null
@@ -1,11 +0,0 @@
---- orig.cascade/2.2.0/Makefile.in	2010-08-05 18:13:21.000000000 +0200
-+++ cascade/2.2.0/Makefile.in	2010-09-30 15:49:04.000000000 +0200
-@@ -195,7 +195,7 @@
- #endif
- MAYBE_OPT = 
- #SUBDIRS = include bases51 misc src $(MAYBE_OPT) data manual
--SUBDIRS = include misc bases51 src $(MAYBE_OPT) data manual
-+SUBDIRS = include misc bases51 src $(MAYBE_OPT) data
- 
- #dist_doc_DATA = README
- EXTRA_DIST = README history.txt
diff --git a/cascade-2.2.04-drop-dcasrn.patch b/cascade-2.2.04-drop-dcasrn.patch
deleted file mode 100644
index 5094bf8ea1a..00000000000
--- a/cascade-2.2.04-drop-dcasrn.patch
+++ /dev/null
@@ -1,38 +0,0 @@
-diff --git a/src/dcasrn.F b/src/dcasrn.F
-index f707c72..61be44c 100644
---- a/src/dcasrn.F
-+++ b/src/dcasrn.F
-@@ -1,20 +1,3 @@
--      DOUBLE PRECISION FUNCTION dcasrn(i)
--
--      DOUBLE PRECISION DR(1)
--      DOUBLE PRECISION TWOM24
--      PARAMETER (TWOM24 = 2.D0**(-24))
--      Real Rvec(2)
--	Integer i
--      CALL RANLUX(RVEC,2)
--      DR(1) = DBLE (RVEC(1)) + DBLE (RVEC(2)) * TWOM24
--c      CALL RM48 (DR,1)
--      dcasrn = DR(1)
--
--
--      RETURN
--      END
--
--
-       SUBROUTINE dcasrnv(RVEC,LENV)
- 
-       Integer lenv,I
-diff --git a/src/Makefile.in b/src/Makefile.in
-index 2f2d255..5aed8f2 100644
---- a/src/Makefile.in
-+++ b/src/Makefile.in
-@@ -37,7 +37,7 @@ PRE_UNINSTALL = :
- POST_UNINSTALL = :
- build_triplet = @build@
- host_triplet = @host@
--bin_PROGRAMS = cascade$(EXEEXT)
-+bin_PROGRAMS =
- subdir = src
- DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
- ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
diff --git a/cascade.spec b/cascade.spec
deleted file mode 100644
index ba65e36e26c..00000000000
--- a/cascade.spec
+++ /dev/null
@@ -1,51 +0,0 @@
-### RPM external cascade 2.2.04
-
-Source: http://cern.ch/service-spi/external/MCGenerators/distribution/%{n}/%{n}-%{realversion}-src.tgz
-Patch0: cascade-2.2.0-nomanual
-Patch1: cascade-2.2.04-getenv
-# Drop dcasrn symbol, which we need to redifine in CMSSW. Do not build cascade
-# executable, since it would use the wrong symbol in anycase.
-Patch2: cascade-2.2.04-drop-dcasrn
-Requires: lhapdf pythia6
-
-%define keep_archives true
-
-%prep
-rm -rf %{n}
-%setup -q -n %{n}/%{realversion}
-%patch0 -p2
-%patch1 -p2
-%patch2 -p1
-
-# Notice that cascade expects a flat pythia installation,
-# where libraries and headers are all in the same place.
-# Since the source code is not actually needed, we point
-# it to the library location so that it links correctly.
-PYTHIA="$PYTHIA6_ROOT"
-LHAPDF="$LHAPDF_ROOT"
-GCC10_FFLAGS=""
-if [[ `gcc --version | head -1 | cut -d' ' -f3 | cut -d. -f1,2,3 | tr -d .` -gt 1000 ]] ; then GCC10_FFLAGS="-fallow-argument-mismatch" ; fi
-F77="$(which gfortran) -fPIC $GCC10_FFLAGS"
-PLATF_CONFIG_OPTS="--enable-static --disable-shared"
-LIBS="-lstdc++ -lz"
-
-# Update to detect aarch64 and ppc64le
-rm -f ./config.{sub,guess}
-%get_config_sub ./config.sub
-%get_config_guess ./config.guess
-chmod +x ./config.{sub,guess}
-
-./configure $PLATF_CONFIG_OPTS --with-pythia6=$PYTHIA  --with-lhapdf=$LHAPDF --prefix=%i F77="$F77" LIBS="$LIBS" 
-%build
-make %makeprocesses
-
-%install
-make install
-
-# In case we build archive libraries we need to merge all of them, because
-# otherwise that results some missing symbol due to a circular dependency among
-# them which cannot be solved by reshuffling the various -l statements.
-cd %{i}/lib
-find . -name '*.a' -exec ar -x {} \;
-ar rcs libcascade_merged.a *.o
-rm -rf *.o
diff --git a/charybdis.spec b/charybdis.spec
deleted file mode 100644
index 707c67e9191..00000000000
--- a/charybdis.spec
+++ /dev/null
@@ -1,31 +0,0 @@
-### RPM external charybdis 1.003
-Source: http://cern.ch/service-spi/external/MCGenerators/distribution/%{n}/%{n}-%{realversion}-src.tgz
-Patch0: charybdis-1003-macosx
-Patch1: charybdis-1.003-archive-only
-
-Requires: pythia6
-Requires: lhapdf
-Requires: zlib
-
-%define keep_archives true
-
-%prep
-%setup -q -n %{n}/%{realversion}
-%patch0 -p3
-# On osx we build only the archive libraries to avoid issues with the common
-# blocks.
-case %cmsos in
-  osx*)
-%patch1 -p3
-  ;;
-esac
-./configure --lcgplatform=%cmsplatf --pythia_hadronization
-
-%build
-make FC="`which gfortran` -fPIC" PYTHIA6_ROOT=$PYTHIA6_ROOT LHAPDF_ROOT=$LHAPDF_ROOT ZLIB_ROOT=$ZLIB_ROOT
-
-%install
-tar -c lib include | tar -x -C %i
-find %i/lib/archive -name "*.a" -exec mv {} %i/lib \;
-rm -rf %i/lib/archive
-
diff --git a/cmssw-tool-conf.spec b/cmssw-tool-conf.spec
index 0515602d8d0..85f1c0da767 100644
--- a/cmssw-tool-conf.spec
+++ b/cmssw-tool-conf.spec
@@ -12,7 +12,6 @@ Requires: starlight
 Requires: alpgen
 Requires: boost
 Requires: bz2lib
-Requires: charybdis
 Requires: classlib
 Requires: clhep
 Requires: coral
@@ -39,14 +38,11 @@ Requires: hector
 Requires: hepmc
 Requires: hepmc3
 Requires: heppdt
-Requires: herwig
 Requires: herwig7
-Requires: hydjet
 Requires: hydjet2
 Requires: ittnotify
 Requires: jemalloc
 Requires: jemalloc-debug
-Requires: jimmy
 Requires: json
 Requires: ktjet
 Requires: lhapdf
@@ -58,7 +54,6 @@ Requires: libxml2
 Requires: lwtnn
 Requires: meschach
 Requires: pcre2
-Requires: photos
 Requires: photospp
 Requires: pyquen
 Requires: pythia6
@@ -75,10 +70,8 @@ Requires: ucx
 Requires: openmpi
 Requires: sigcpp
 Requires: sqlite
-Requires: tauola
 Requires: tauolapp
 Requires: thepeg
-Requires: toprex
 Requires: libuuid
 Requires: xerces-c
 Requires: dcap
@@ -94,7 +87,6 @@ Requires: grpc
 Requires: onnxruntime
 Requires: triton-inference-client
 Requires: hdf5
-Requires: cascade
 Requires: yoda
 Requires: fftw3
 Requires: fftjet
diff --git a/herwig.spec b/herwig.spec
deleted file mode 100644
index f87ee531182..00000000000
--- a/herwig.spec
+++ /dev/null
@@ -1,40 +0,0 @@
-### RPM external herwig 6.521
-Source: http://cern.ch/service-spi/external/MCGenerators/distribution/%{n}/%{n}-%{realversion}-src.tgz
-Requires: lhapdf photos 
-Patch1: herwig-6.520-tauoladummy
-
-%define keep_archives true
-
-%prep
-%setup -q -n %n/%{realversion}
-F77="$(which gfortran) -fPIC"
-PLATF_CONFIG_OPTS="--disable-shared --enable-static"
-
-%patch1 -p2
-
-# Update to detect aarch64 and ppc64le
-rm -f ./config/config.{sub,guess}
-%get_config_sub ./config/config.sub
-%get_config_guess ./config/config.guess
-chmod +x ./config/config.{sub,guess}
-
-./configure $PLATF_CONFIG_OPTS --prefix=%i F77="$F77"
-
-%build
-make %{makeprocesses} LHAPDF_ROOT=$LHAPDF_ROOT PHOTOS_ROOT=$PHOTOS_ROOT
-
-make check
-
-%install
-make install
-
-# then hack include area as jimmy depends on missing header file..
-# but only on slc*. On macosx HERWIG65.INC == herwig65.inc
-# what is actually needed is a link to herwig6510.inc
-%ifos darwin
-ln -sf herwig6521.inc %{i}/include/herwig65.inc
-%else
-ln -sf HERWIG65.INC %{i}/include/herwig65.inc
-%endif
-
-rm -rf %i/lib/*.la
diff --git a/jimmy.spec b/jimmy.spec
deleted file mode 100644
index edaf36e9bda..00000000000
--- a/jimmy.spec
+++ /dev/null
@@ -1,25 +0,0 @@
-### RPM external jimmy 4.2
-
-Requires: herwig
-Source: http://service-spi.web.cern.ch/service-spi/external/MCGenerators/distribution/%{n}/%{n}-%{realversion}-src.tgz
-Patch0: jimmy-4.2-configure-update
-
-%define keep_archives true
-
-%prep
-%setup -q -n %{n}/%{realversion}
-%patch0 -p2
-
-%build
-./configure $PLATF_CONFIG_OPTS --with-herwig=$HERWIG_ROOT
-# Looks like ./configure does not do all it should do to have our
-# version of herwig picked up at link time.
-# Workaround until they fix the GENESER makefiles is to define
-# the variable and use it directly inside "Makeshared".
-make HERWIG_ROOT=$HERWIG_ROOT FFLAGS=-std=legacy lib_archive
-
-%install
-tar -c lib include | tar -x -C %i
-find %i/lib/archive -name "*.a" -exec mv {} %i/lib \;
-rm -rf %i/lib/archive
-
diff --git a/photos.spec b/photos.spec
deleted file mode 100644
index 52e49eea4d5..00000000000
--- a/photos.spec
+++ /dev/null
@@ -1,23 +0,0 @@
-### RPM external photos 215.5
-
-Source: http://cern.ch/service-spi/external/MCGenerators/distribution/%{n}/%{n}-%{realversion}-src.tgz
-Patch0: photos-215.5-update-configure
-%define keep_archives true
-
-%prep
-%setup -q -n %{n}/%{realversion}
-%patch0 -p2
-
-%build
-PLATF_CONFIG_OPTS="--enable-static --disable-shared"
-./configure --lcgplatform=%cmsplatf $PLATF_CONFIG_OPTS 
-%ifos darwin
-perl -p -i -e "s|libphotos.so|libphotos.dylib|g" Makefile ;;
-%endif
-make 
-
-%install
-tar -c lib include | tar -x -C %i
-find %i/lib/archive -name "*.a" -exec mv {} %i/lib \;
-rm -rf %i/lib/archive
-
diff --git a/tauola.spec b/tauola.spec
deleted file mode 100644
index 245057344d7..00000000000
--- a/tauola.spec
+++ /dev/null
@@ -1,35 +0,0 @@
-### RPM external tauola 27.121.5
-Source: http://cern.ch/service-spi/external/MCGenerators/distribution/%{n}/%{n}-%{realversion}-src.tgz
-Patch1: tauola-27.121.5-gfortran-taueta
-Patch2: tauola-27.121-gfortran-tauola-srs
-Patch3: tauola-27.121.5-configure-makefile-update
-# Notice that on macosx we don't build shared libraries, so the following
-# requires are not really mandatory, but we keep them for consistency with the
-# linux build.
-Requires: pythia6
-Requires: photos
-
-%define keep_archives true
-
-%prep
-%setup -q -n %{n}/%{realversion}
-# Remove options by hand since it looks like they have
-# the bad habit of republishing sources.
-perl -p -i -e 's|-fno-globals||g;s|-finit-local-zero||g;s|-fugly-logint||g;s|-fugly-complex||' configure
-# Removed since this appears to have already been applied in the new tarball...
-# Sigh...
-%patch1 -p2
-%patch2 -p2
-%patch3 -p2
-
-FC="$(which gfortran) -fPIC"
-./configure --lcgplatform=%cmsplatf --with-pythia6libs=$PYTHIA6_ROOT/lib FC="$FC"
-perl -p -i -e "s|FC = gfortran|FC = $(which gfortran) -fPIC|;s|CC = gcc|CC = $(which gcc) -fPIC|" config.mk
-%build
-make PHOTOS_ROOT=$PHOTOS_ROOT
-
-%install
-tar -c lib include | tar -x -C %i
-find %i/lib/archive -name "*.a" -exec mv {} %i/lib \;
-rm -rf %i/lib/archive
-
diff --git a/toprex.spec b/toprex.spec
deleted file mode 100644
index d43755ce30a..00000000000
--- a/toprex.spec
+++ /dev/null
@@ -1,28 +0,0 @@
-### RPM external toprex 4.23
-
-Source: http://service-spi.web.cern.ch/service-spi/external/MCGenerators/distribution/%{n}/%{n}-%{realversion}-src.tgz
-Patch1: toprex-4.23-macosx
-Patch2: toprex-4.23-archive-only
-Requires: pythia6
-
-%define keep_archives true
-
-%prep
-%setup -q -n %{n}/%{realversion}
-# Remove options by hand since it looks like they have
-# the bad habit of republishing sources.
-perl -p -i -e 's|-fno-globals||g;s|-finit-local-zero||g;s|-fugly-logint||g' configure
-
-%patch1 -p3
-%patch2 -p3
-
-%build
-FC="$(which gfortran) -fPIC"
-
-./configure --lcgplatform=%cmsplatf
-make FC="$FC" PYTHIA6_ROOT=$PYTHIA6_ROOT
-
-%install
-tar -c lib include | tar -x -C %i
-find %i/lib/archive -name "*.a" -exec mv {} %i/lib \;
-rm -rf %i/lib/archive