diff --git a/references/git-and-tooling-scars.md b/references/git-and-tooling-scars.md
index 80c227c..bffbddc 100644
--- a/references/git-and-tooling-scars.md
+++ b/references/git-and-tooling-scars.md
@@ -57,6 +57,13 @@
 - **Remove only paths you created, by exact name.** Never `rm` a glob in a
   shared directory such as `%TEMP%`: a Soul pass deleted other agents' scratch
   and job markers that way. Keep scratch under the session scratchpad.
+- **Clean scratch build output before a Self run ends.** Cargo `target`
+  directories run 5 to 20 GB each, and Soul and Hands scratch builds left about
+  345 GB of them in one Mind's workspace until `/` reached 97% (2026-11-13).
+  Build in a scratch dir named for the pass, and at run end delete that pass's
+  `target*` dirs by exact name unless a root list or an open run pins them
+  (`CACHEDIR.TAG` marks a cargo target). A build run by docker is root-owned: put
+  its dir on a root list in `/opt/commons/handoff` instead of failing the `rm`.
 - **Name the repo on every git command: `git -C <abs repo>`.** The shell cwd
   resets between calls, and a chained `git add && git commit && git push` once
   ran in the wrong repo and pushed its dirty tree. Read the branch line of