Mystery white coating on equipment

[Drinksahoy]

after the move in June I haven’t touched my big batch equipment. Just my one gallon equipment.

I went to break out some stuff for a 5 gal mead I have going and I discovered this inside my bucket.

Not sure what this powder is or if anyone else might know:

Well can’t add images from my phone.
Maybe someone just knows what I’m talking about, otherwise I’ll add a picture when I get home.

 

[flars]

Did you leave some Star San solution in the bucket? PBW solution or other cleaner?

 

[MHBT]

Or maybe water stains? or like Flars said pbw residue

 

[Aaron Beers]

Is the equipment stainless steel or aluminum?

 

[Drinksahoy]

Is the equipment stainless steel or aluminum?

Stainless steel