Ikeep old jugs of glow fuel justfor engine cleaning. Irecently had quite at task freeing up a brand new O.S 1:20 Ft. It was so gummed up from setting all those years that it felt like things were welded together.After a couple days soaking, we were able to get the crank to turn over, but the bearing cages were still froze solid so the bearings were sliding, not rolling. It took two, serval hour long, sessions in the heated ultra-sonic cleaner in a beaker of glow fuel before the bearings finally loosened up. Once I got them running around the track OK, the next session broke loose all of the grease chunks and things were well.

I would pull the back plate and then the soak the engine. That allows the fuel to get in easier and do it's job, and you can also see the condition of the bearings that way.

Don