My favorite for this type of cleaning was the now generally banned carbon tetrachloride - a very powerful cleaner, non-flammable and prone to cause liver damage (although, despite the fact that I once used rags soaked with it to clean the rails of my HO gauge model trains, I still take my before dinner tipple and a bit of wine with sans any apparent distress). I find that a bit of braid cleaner squirted in to the motor in the general direction of the commutator keeps things running a bit smoother and faster. I also use braid cleaner soaked pipe cleaners to clean my braids before running- and, when allowed, between heats. It is truly amazing to see the amount of dirt that comes off with each application! Use commercial electrical contact cleaner with caution. Some of them are not kind to styrene. They won't dmage the motor but could cause an unfortunate redecoration of any neighboring body bits.
EM
EM
