It is not paint, but what else do you call it

Bench outside a condominium

Detail of the sign on the sidewalk

I saw this sign stuck to the sidewalk outside a condominium building just down the street from where I live. The signs all said, "Caution Wet Paint on benches".

A perfectly sensible sign. If there is wet paint you should want passersby to know about it. But it was not paint. It was stain, or varnish.

So you have two choices. Do you opt for the accurate sign? (Wet Varnish) Or do you opt for the one that everyone will understand? (Wet Paint)

And here I say go for clarity, even if it is not 100% accurate. I know, it sounds like heresy, but you need to think about the goal. You don't want someone to sit on the bench, and "Wet Paint" conveys all the meaning you need.