diff --git a/browser_patches/firefox-beta/clean.sh b/browser_patches/firefox-beta/clean.sh
index 468c5024df..d94baf33a3 100755
--- a/browser_patches/firefox-beta/clean.sh
+++ b/browser_patches/firefox-beta/clean.sh
@@ -16,5 +16,5 @@ if [[ -d $OBJ_FOLDER ]]; then
 fi
 
 if [[ -f "mach" ]]; then
-  ./mach clobber
+  ./mach clobber || true
 fi
diff --git a/browser_patches/firefox/clean.sh b/browser_patches/firefox/clean.sh
index 468c5024df..d94baf33a3 100755
--- a/browser_patches/firefox/clean.sh
+++ b/browser_patches/firefox/clean.sh
@@ -16,5 +16,5 @@ if [[ -d $OBJ_FOLDER ]]; then
 fi
 
 if [[ -f "mach" ]]; then
-  ./mach clobber
+  ./mach clobber || true
 fi