Your standard everyday white grease base polishing compound is what you want, you can follow up with blue compound if you want. You need a wheel or 3 (depending on buffer size) for each compound. When you are done with the compounds Blue Magic on it's own wheel will really bring up the shine. White is not very aggressive at all but you can still go through the thin chrome, don't use anything more aggressive. You may still go through the chrome with the white, you'll see an area that doesn't look like the rest of the wrench, it'll look like a stain in the chrome, when you try to buff it out it will expand, STOP there and leave it as you are already through the chrome and just making it worse.
I've polished probably a couple hundred wrenches, my own and some local mechanics. I'm sure you'll get responses disagreeing with polishing, that's their opinion, if you want pretty wrenches by all means go for it.
One of the shop owners I've done work for said he gets it done because when he allows a customer into a bay to show him something the customer sees shiny Snap On tools in a clean garage, it shows he takes pride in his work.
