Cleaning dye build up off a burnisher

[stormcrow]

I've have a cocobolo burnisher from ProEdge and also one of the Armatige burnishers both on a bench grinder.

I've noticed that I get some dye build up that is transferring onto my edges what is the best way of cleaning these burnishers.

I have been using canvas soaked in isopropyl wrapped over the edges of scrap leather is this the best way or is there something else I can use instead of isopropyl to remove the dye build up.

Is a fine grit sandpaper a better option, I know cocobolo is toxic so  I would have to use a mask but to be honest I would rather not sand in case I damage the profile of the grooves.

[bgl500]

The individual I bought my burnishers from suggested fine grit sandpaper to clean the burnisher.

[alpha2]

Probably doesn't help this particular issue, but I have different burnishers for "raw", "clean" leather, and dyed leather. Also, I can't imagine that cocobolo in the amounts we're talking about, is particularly toxic. PPM, and all that. It's not like you'll be doing it commercially for years. 

Jeff