diff --git a/etc/ci/buildbot_steps.yml b/etc/ci/buildbot_steps.yml
index d84923c1871..8727fdcedae 100644
--- a/etc/ci/buildbot_steps.yml
+++ b/etc/ci/buildbot_steps.yml
@@ -79,12 +79,14 @@ mac-nightly:
 linux-rel-intermittent:
   - ./mach clean-nightlies --keep 3 --force
   - ./mach clean-cargo-cache --keep 3 --force
+  - ./mach clean
   - ./mach build --release
   - ./etc/ci/check_intermittents.sh --log-raw intermittents.log
 
 linux-rel-nogate:
   - ./mach clean-nightlies --keep 3 --force
   - ./mach clean-cargo-cache --keep 3 --force
+  - ./mach clean
   - ./mach build --release
   - python ./etc/ci/chaos_monkey_test.py
   - env RUSTFLAGS= bash ./etc/ci/mutation_test.sh
@@ -102,6 +104,7 @@ linux-dev:
   commands:
     - ./mach clean-nightlies --keep 3 --force
     - ./mach clean-cargo-cache --keep 3 --force
+    - ./mach clean
     - ./mach test-tidy --no-progress --all
     - ./mach test-tidy --no-progress --self-test
     - ./mach build --dev
@@ -121,6 +124,7 @@ linux-rel-wpt:
   commands:
     - ./mach clean-nightlies --keep 3 --force
     - ./mach clean-cargo-cache --keep 3 --force
+    - ./mach clean
     - ./mach build --release --with-debug-assertions
     - ./mach test-wpt-failure
     - ./mach test-wpt --release --processes 24 --total-chunks 2 --this-chunk 1 --log-raw test-wpt.log --log-errorsummary wpt-errorsummary.log --always-succeed
@@ -134,6 +138,7 @@ linux-rel-css:
   commands:
     - ./mach clean-nightlies --keep 3 --force
     - ./mach clean-cargo-cache --keep 3 --force
+    - ./mach clean
     - ./mach build --release --with-debug-assertions
     - ./mach test-wpt --release --processes 24 --total-chunks 2 --this-chunk 2 --log-raw test-wpt.log --log-errorsummary wpt-errorsummary.log --always-succeed
     - ./mach filter-intermittents wpt-errorsummary.log --log-intermittents intermittents.log --log-filteredsummary filtered-wpt-errorsummary.log --tracker-api default --reporter-api default
@@ -145,6 +150,7 @@ linux-rel-css:
 linux-nightly:
   - ./mach clean-nightlies --keep 3 --force
   - ./mach clean-cargo-cache --keep 3 --force
+  - ./mach clean
   - ./mach build --release
   - ./mach package --release
   - ./mach upload-nightly linux