So after reading a few posts, forgot which forum it was, I wondered something. I always store my empty kegs under pressure with a little Starsan solution in them. My empty fermenters as well. (I have glass and plastic carboys, better bottles)
Some people say you shouldn't store anything in sanitizer. Is this true? They say it breaks down the material. Well my Starsan arrived at my house, full strength, in a plastic bottle, is it not ok to dillute it and leave it in a fermenter/keg (glass, plastic, Stainless steel)
There's a good reason that acids are often stored in plastic containers. For a rather illustrated and very memorable explanation check out the 2nd or 3rd episode, 1st season, of a show called "Breaking Bad". Trust me, it will stick with you...