[Tru_in_Blu]

I don't know if you have metal or plastic zippers. It might make a difference on what kind of solution you might try.

I've used graphite on some zippers in the past. Now that you've sprayed it with WD-40m I don't know if that might cause more problems.

I've also used a simple bar of soap at times when nothing else was available.

You've probably already checked to see if there are any loose threads or other obstructions blocking the zipper's path.

Good luck!