I dunno what a Scotsman would wear, but I just wear my boxers.

As for cleaning and washing, I just keep my wetty wet for a couple of days. It doesnt do them any harm, then I just chuck it on the clothesline till its dry and stuff it in my wetty-bag, same with my booties.

My wetty is a 5x3mm with some type of Titanium weave? - Its super warm though.