Gib Bogle wrote:
When a polyurethaned floor (for example) has a small mark that needs
touching up, what's the recommended procedure? I've sanded the spot
with 1000 grit wet&dry, and tried applying a dab of poly with a small
brush. The flaw in that approach was immediately obvious, since the
newly applied poly surface was raised and clearly not going to blend in.
I wiped it off with turps, back to the drawing board. It seems that it
might be necessary to thin the poly in order to be able to feather the
edges. If so, in what proportion, and if not, what else?

Apply the varnish with a rag or sponge?