diff --git a/bin/clean.sh b/bin/clean.sh
index b76e392..a72c891 100755
--- a/bin/clean.sh
+++ b/bin/clean.sh
@@ -122,7 +122,7 @@ whitelist_skipped_count=0
 
 # shellcheck disable=SC2329
 note_activity() {
-    if [[ $TRACK_SECTION -eq 1 ]]; then
+    if [[ "${TRACK_SECTION:-0}" == "1" ]]; then
         SECTION_ACTIVITY=1
     fi
 }
@@ -183,7 +183,7 @@ start_section() {
 end_section() {
     stop_section_spinner
 
-    if [[ $TRACK_SECTION -eq 1 && $SECTION_ACTIVITY -eq 0 ]]; then
+    if [[ "${TRACK_SECTION:-0}" == "1" && "${SECTION_ACTIVITY:-0}" == "0" ]]; then
         echo -e "  ${GREEN}${ICON_SUCCESS}${NC} Nothing to clean"
     fi
     TRACK_SECTION=0
@@ -275,7 +275,7 @@ safe_clean() {
         return 0
     fi
 
-    if [[ $TRACK_SECTION -eq 1 && $SECTION_ACTIVITY -eq 0 ]]; then
+    if [[ "${TRACK_SECTION:-0}" == "1" && "${SECTION_ACTIVITY:-0}" == "0" ]]; then
         stop_section_spinner
     fi
 
diff --git a/lib/clean/user.sh b/lib/clean/user.sh
index f4b810f..e16ff10 100644
--- a/lib/clean/user.sh
+++ b/lib/clean/user.sh
@@ -131,7 +131,14 @@ clean_mail_downloads() {
         if [[ -d "$target_path" ]]; then
             local dir_size_kb=0
             dir_size_kb=$(get_path_size_kb "$target_path")
-            if [[ $dir_size_kb -lt ${MOLE_MAIL_DOWNLOADS_MIN_KB:-5120} ]]; then
+            if ! [[ "$dir_size_kb" =~ ^[0-9]+$ ]]; then
+                dir_size_kb=0
+            fi
+            local min_kb="${MOLE_MAIL_DOWNLOADS_MIN_KB:-5120}"
+            if ! [[ "$min_kb" =~ ^[0-9]+$ ]]; then
+                min_kb=5120
+            fi
+            if [[ "$dir_size_kb" -lt "$min_kb" ]]; then
                 continue
             fi
             while IFS= read -r -d '' file_path; do
diff --git a/lib/core/base.sh b/lib/core/base.sh
index eda3757..5bfbfbf 100644
--- a/lib/core/base.sh
+++ b/lib/core/base.sh
@@ -569,7 +569,7 @@ start_section() {
 # End a section
 # Shows "Nothing to tidy" if no activity was recorded
 end_section() {
-    if [[ $TRACK_SECTION -eq 1 && $SECTION_ACTIVITY -eq 0 ]]; then
+    if [[ "${TRACK_SECTION:-0}" == "1" && "${SECTION_ACTIVITY:-0}" == "0" ]]; then
         echo -e "  ${GREEN}${ICON_SUCCESS}${NC} Nothing to tidy"
     fi
     TRACK_SECTION=0
@@ -577,7 +577,7 @@ end_section() {
 
 # Mark activity in current section
 note_activity() {
-    if [[ $TRACK_SECTION -eq 1 ]]; then
+    if [[ "${TRACK_SECTION:-0}" == "1" ]]; then
         SECTION_ACTIVITY=1
     fi
 }
diff --git a/lib/core/file_ops.sh b/lib/core/file_ops.sh
index af6d82f..23a9463 100644
--- a/lib/core/file_ops.sh
+++ b/lib/core/file_ops.sh
@@ -269,7 +269,7 @@ get_path_size_kb() {
     # Use || echo 0 to ensure failure in du (e.g. permission error) doesn't exit script under set -e
     # Pipefail would normally cause the pipeline to fail if du fails, but || handle catches it.
     local size
-    size=$(command du -sk "$path" 2> /dev/null | awk '{print $1}' || true)
+    size=$(command du -sk "$path" 2> /dev/null | awk 'NR==1 {print $1; exit}' || true)
 
     # Ensure size is a valid number (fix for non-numeric du output)
     if [[ "$size" =~ ^[0-9]+$ ]]; then