Homebrew PCBs

Skip the metal polish stage.

Shiny is NOT what you're looking for. If anything you should be sanding it
with perhaps 600 grit wet/dry paper.

In addition, who knows what the metal polish leaves behind. Usually a layer
of wax which is part of the product.

The ONLY things I do is use medium steel wool to clean the copper oxide off
the surface and then scrub with a household cleaning product called "Spray
Nine" by Knights. Rinse with water and let dry.

(Apparently similar to "Fantastic" spray cleaner - can't vouch for that).

It's slightly caustic (symbol on bottle) and is a very good degreaser. 

That's all I do and have NEVER had problems with the toner of my vintage HP
LaserJet III sticking.

Your laquer thinners should be enough as well following the steel wool.

Wear rubber gloves so you don't touch the board after cleaning.

 

Sage