What do you use to clean Kewler Kit stainless?

What do y'all use to clean your stainless valves and other parts? I bought a Kewler Kit for a 10 gallon mashe tun cooler. I've been noticing what I can best describe as a watery milk flavor in my all grain batches and wonder if I'm not cleaning it right.
I've just used dish soap and star san. Is there some other method to season the stainless?
thanks,
Txinga

Sorry for the second post.

I forgot to add the other obvious question.

Do y'all think it could be the cooler giving the off flavor?

Txinga

I use oxiclean free and hot water if it needs a soak, otherwise the mash tun just gets rinsed with the hose. My BK gets an oxiclean recirc and quick scrub with a hard bristle brush, then I rinse with the hose.

What is your efficiency looking like? What kind of cooler do you use?

HERE is a link to some descriptions of off-flavors and their causes, I've never heard of milky but watery could be a volume issue or efficiency issue. I'd probably look somewhere else for the off-flavor, I doubt the mash tun is to blame.

Thanks for the link.
the first beer I royally screwed up.ended up very thin. Og really low.
The second, according to the hydrometer I was spot on. The beer doesn't taste watery it's just the off flavor I'm getting reminds me of watered down our maybe iced milk.
The first beer was BMs Krisper Kolsch. The second his Centennial Blonde.