diff --git a/copyparty/up2k.py b/copyparty/up2k.py
index 652054b7..e96f3869 100644
--- a/copyparty/up2k.py
+++ b/copyparty/up2k.py
@@ -700,6 +700,16 @@ class Up2k(object):
                 # indicate scanned without tags
                 tags = {"x": 0}
 
+        if not tags:
+            return 0
+
+        for k in tags.keys():
+            q = "delete from mt where w = ? and ({})".format(
+                " or ".join(["k = ?"] * len(tags))
+            )
+            args = [wark[:16]] + list(tags.keys())
+            write_cur.execute(q, tuple(args))
+
         ret = 0
         for k, v in tags.items():
             q = "insert into mt values (?,?,?)"
diff --git a/docs/notes.sh b/docs/notes.sh
index 6f6e6ce2..d4898113 100644
--- a/docs/notes.sh
+++ b/docs/notes.sh
@@ -67,6 +67,17 @@ wget -S --header='Accept-Encoding: gzip' -U 'MSIE 6.0; SV1' http://127.0.0.1:392
 shab64() { sp=$1; f="$2"; v=0; sz=$(stat -c%s "$f"); while true; do w=$((v+sp*1024*1024)); printf $(tail -c +$((v+1)) "$f" | head -c $((w-v)) | sha512sum | cut -c-64 | sed -r 's/ .*//;s/(..)/\\x\1/g') | base64 -w0 | cut -c-43 | tr '+/' '-_'; v=$w; [ $v -lt $sz ] || break; done; }
 
 
+##
+## sqlite3 stuff
+
+# find dupe metadata keys
+sqlite3 up2k.db 'select mt1.w, mt1.k, mt1.v, mt2.v from mt mt1 inner join mt mt2 on mt1.w = mt2.w where mt1.k = mt2.k and mt1.rowid != mt2.rowid'
+
+# partial reindex by deleting all tags for a list of files
+sqlite3 up2k.db 'select mt1.w from mt mt1 inner join mt mt2 on mt1.w = mt2.w where mt1.k = mt2.k and mt1.rowid != mt2.rowid'  > warks
+cat warks | while IFS= read -r x; do sqlite3 up2k.db "delete from mt where w = '$x'"; done
+
+
 ##
 ## vscode