diff --git a/build-fuzz-corpus-multiple-sizes.sh b/build-fuzz-corpus-multiple-sizes.sh
index 58d6f5b6..88bfc49b 100755
--- a/build-fuzz-corpus-multiple-sizes.sh
+++ b/build-fuzz-corpus-multiple-sizes.sh
@@ -1,10 +1,10 @@
 #!/bin/bash
+set -euxo pipefail
 mkdir "fuzz/corpus/fuzz_$1_recombination_sources" || true
-mv "fuzz/corpus/fuzz_$1/*" "fuzz/corpus/fuzz_$1_recombination_sources"
 for size in "${@:2}"; do
-  mv "fuzz/corpus/fuzz_$1_pre_fresh_blood/*" "fuzz/corpus/fuzz_$1_recombination_sources" || true
+  rm -rf "fuzz/corpus/fuzz_$1_pre_fresh_blood" || true
+  mv "fuzz/corpus/fuzz_$1/*" "fuzz/corpus/fuzz_$1_recombination_sources" || true
   ./build-fuzz-corpus-multiple-restarts.sh "$1" "$size"
-  find "fuzz/corpus/fuzz_$1_pre_fresh_blood" -type -f -size "-${size}c" -exec mv '{}' "fuzz/corpus/fuzz_$1" ';'
   find "fuzz/corpus/fuzz_$1_recombination_sources" -type -f -size "-${size}c" -exec mv '{}' "fuzz/corpus/fuzz_$1" ';'
   ./fuzz-until-converged.sh "$1" "$size"
 done
\ No newline at end of file