Help me remove white deposit in my kegs , is it beer stone ?

Hi keg for years, and this problem is growing : I having a scale or "beer stone" problem in my kegs. washing with PSB, TSP, Caustic (2,5%) , soap, or lime removal doesn't seem to remove my white deposit. Any idea ?

I've never had beer stone appear "white". My guess is a mineral buildup, possibly the result of hard water.

The one thing apparently not tried is something acidic. Try mixing up a white vinegar & water solution, maybe a cup of vinegar in a quart of water (or a strong Star San solution - doubled, just for grins) pour it in, give it a good swirl, let it sit for awhile, repeat a couple of times, then dump into the next keg and rinse out the first, and see how it looks...

Cheers!

[edit] I just noticed the "lime removal" part. I assume that was something acidic (CLR, perhaps). If that's true, I'm not sure what you're looking at...

Good long soak in starsan gets rid of white stuff in my bottles, carboys, etc.

this article on byo said use foaming acid cleaner by spartan chemicals but i couldn't find it anywhere online. But it looks like acid is the way to go.
http://byo.com/equipment/item/1660-yearly-brewery-checkup

Most kegs look nice and shiny inside when you get them, from the acidic soda syrup that used to be inside. So it's most likely beerstone. I use saniclean, about 3oz for 5 gal should clean it up. If it's real bad just attach a scotchbrite pad to a stick and scrub it manually with BKF. That will get rid of it very easily.

Heated white vinegar can be used to remove hard deposits from things. Maybe give that a go. I believe it has to be pretty warm though, almost boiling

Have you tried oxiclean free? That stuff works like a charm!

Edit... nevermind! PBW is basically the same thing. Try the vinegar route