I have a permanent marker pen. On its side it says, "Suitable for use on CD-R, DVD-R, glass, wood, metal, vinyl, plastic etc.
Not suitable for children"
The enemas I have to use before my radiotherapy sessions are labelled "For external use only". I want to ask "How???"
I see lots of firms advertising 'aluminium windows'. Personally, I'll stick to glass ones, as I suspect that it will be a lot easier to see through them ;-)
The swimming pool in central Ipswich used to have a sign in the showers stating "Trunks must be worn always". I've been faithfully following that instruction for years and they're beginning to make me very itchy!
I refuse to follow the instructions that came with my teapot though. I got arrested for indecent exposure when my neighbour complained after the last time I complied: "After use, wash well and stand upside down on draining board"