diff --git a/build/workspaces/clean-workspaces.sh b/build/workspaces/clean-workspaces.sh
index c5881d72cf..fa7a6f626e 100755
--- a/build/workspaces/clean-workspaces.sh
+++ b/build/workspaces/clean-workspaces.sh
@@ -38,16 +38,17 @@ if [ "$preserve_libs" != "true" ]; then
   (cd ../../libraries/source/spidermonkey && rm -rf ./lib/*.a && rm -rf ./lib/*.so)
   (cd ../../libraries/source/spidermonkey && rm -rf ./include-unix-debug)
   (cd ../../libraries/source/spidermonkey && rm -rf ./include-unix-release)
-  (cd ../../libraries/source/spidermonkey && rm -rf ./mozjs-68.12.1)
+  (cd ../../libraries/source/spidermonkey && rm -rf ./mozjs-91.13.1)
 fi
 
 # Still delete the directory of previous SpiderMonkey versions to
 # avoid wasting disk space if people clean workspaces after updating.
+(cd ../../libraries/source/spidermonkey && rm -rf ./mozjs-78.6.0)
+(cd ../../libraries/source/spidermonkey && rm -rf ./mozjs-68.12.1)
 (cd ../../libraries/source/spidermonkey && rm -rf ./mozjs-62.9.1)
 (cd ../../libraries/source/spidermonkey && rm -rf ./mozjs-52.9.1pre1)
 (cd ../../libraries/source/spidermonkey && rm -rf ./mozjs-45.0.2)
 (cd ../../libraries/source/spidermonkey && rm -rf ./mozjs-38.0.0)
-(cd ../../libraries/source/spidermonkey && rm -rf ./mozjs-38.0.0)
 (cd ../../libraries/source/spidermonkey && rm -rf ./mozjs31)
 (cd ../../libraries/source/spidermonkey && rm -rf ./mozjs24)