Clear oil, also known as fish oil, has certain toxicity.

Varnish is a kind of paint.

Varnish is a coating made of resin, linseed oil or turpentine.

Clear oil penetrated into the wood.

Clear oil penetrates into the wood and forms a soft film protection layer on the wood surface.

The varnish forms a hard protective layer.

Varnish A popular varnish is to form a thick and hard protective layer on the surface of wood, just like sticking a thin layer of glass.

The customary name of an old painter.

Now old painters are used to calling varnish clear oil, which is what old painters used to call it. Clear oil and varnish are two completely different things.