Corny keg or beer keg?
Beer kegs have beer. Even really old kegs, unless it's been contaminated somehow, just has beer in it. I wouldn't drink it, but it's just liquid beer. Not nasty, not thick or syrupy... just beer.
Corny kegs (soda kegs) on the other hand can be nasty.
Keg #1: Bourbon/Oak Vanilla Porter
Keg #2: Cascadian Stout
Keg #3: BMC West
Bottled: Mjolnir Mead, Lazy Daze Hefe, The Bollocks ESB, Dark Matter stout.