diff --git a/t/102-empty/silencetest.do b/t/102-empty/silencetest.do
index b0e7c9e..3364cf0 100644
--- a/t/102-empty/silencetest.do
+++ b/t/102-empty/silencetest.do
@@ -1,3 +1,7 @@
+# This may have been leftover from a previous run, when switching
+# between "real" redo and minimal/do, so clean it up.
+rm -f silence
+
 echo 'echo hello' >silence.do
 redo silence
 [ -e silence ] || exit 55
diff --git a/t/102-empty/touchtest.do b/t/102-empty/touchtest.do
index 95c6e64..2b60d8f 100644
--- a/t/102-empty/touchtest.do
+++ b/t/102-empty/touchtest.do
@@ -1,3 +1,7 @@
+# This may have been leftover from a previous run, when switching
+# between "real" redo and minimal/do, so clean it up.
+rm -f touch1
+
 echo 'echo hello' >touch1.do
 redo touch1
 [ -e touch1 ] || exit 55
diff --git a/t/201-fail/all.do b/t/201-fail/all.do
index 0275806..8857ea6 100644
--- a/t/201-fail/all.do
+++ b/t/201-fail/all.do
@@ -12,3 +12,7 @@ touch fail
 ../flush-cache
 # since we created this file by hand, fail.do won't run, so it won't fail.
 redo-ifchange fail >/dev/null 2>&1 || exit 55  # expected to pass
+
+# Make sure we don't leave this lying around for future runs, or redo
+# might mark it as "manually modified" (since we did!)
+rm -f fail
diff --git a/t/350-deps/overwrite.do b/t/350-deps/overwrite.do
index 5145b75..7af7729 100644
--- a/t/350-deps/overwrite.do
+++ b/t/350-deps/overwrite.do
@@ -1,5 +1,4 @@
 . ../skip-if-minimal-do.sh
-
 redo overwrite1 2>&1 && exit 55
 redo overwrite2 2>&1 && exit 56
 redo overwrite3 2>&1 && exit 57
diff --git a/t/350-deps/test1.do b/t/350-deps/test1.do
index 47fb596..6e4f57d 100644
--- a/t/350-deps/test1.do
+++ b/t/350-deps/test1.do
@@ -1,3 +1,7 @@
+# This may have been leftover from a previous run, when switching
+# between "real" redo and minimal/do, so clean it up.
+rm -f t1a
+
 # force-rebuild t1dep
 redo t1dep
 
diff --git a/t/355-deps-cyclic/all.do b/t/355-deps-cyclic/all.do
index a835661..3f9c82a 100644
--- a/t/355-deps-cyclic/all.do
+++ b/t/355-deps-cyclic/all.do
@@ -1,2 +1,5 @@
+# minimal/do doesn't need to "support" cyclic dependencies, because
+# they're always a bug in the .do scripts :)
 . ../skip-if-minimal-do.sh
+
 ! redo a >/dev/null 2>&1 || exit 204
diff --git a/t/360-symlinks/all.do b/t/360-symlinks/all.do
index a5259e8..865207d 100644
--- a/t/360-symlinks/all.do
+++ b/t/360-symlinks/all.do
@@ -11,6 +11,8 @@ redo-ifchange b
 d2=$(cat b.did)
 [ "$d1" = "$d2" ] || exit 12
 
+. ../skip-if-minimal-do.sh
+
 # forcibly changing a should rebuild b.
 # a is already symlink to a.extra, but redo shouldn't care about the
 # target of symlinks, so it shouldn't freak out that a.extra has changed.