Salt removal on upvc frames

Hi fellas, I removed salt of some windows earlier in the week, had to scrape it off. Any ideas what to use to get it off the frames as usual stuff  wouldn’t touch it ?  Thanks James. 

Oh damn that looks heavy. I wonder if a bathroom limescale remover spray would do the trick?  I have a clear glass kettle, and it removes heavy limescale off the inside of that really easily. You will need to leave it on for a short while first though.

uPVC cleaner from Nustock who sell uPVC stuff. Haven't came across anything that it couldn't remove!