What's your rule for when to clean up a plane vs. leave the patina intact?

Been running an Etsy shop for a couple years, mostly home decor and random vintage finds. A few months ago I started picking up old hand tools at estate sales and thrift stores planes, chisels, draw knives, that kind of thing cleaning them up a bit and listing them. Margins are genuinely surprising me.

The thing is I already woodwork, so I can tell a Stanley No. 4 that just needs a rust clean from one that's actually garbage. That knowledge gap seems to be where the money is. Guys at estate sales just see an old rusty tool and price it at two bucks. I see a collectible with a waiting market.

What I keep running into is knowing when to restore versus sell asis. I cleaned up a plane last month, listed it for $65, sold in two days. But I've seen people say restoration kills value on certain vintage tools, and I don't want to leave money on the table by wiping off patina that collectors actually want.

Anyone here flipping vintage tools specifically? How are you deciding what gets cleaned and what ships with the rust and grime intact? Feels like there's a real learning curve around which brands and eras collectors are chasing right now.