They look identical to a regular Mabuchi or Johnson motor, but they're cranked-up inside. You can really put some gear to a silver can motor, but if you do it to a Sport-Tuned (black can), they go "POOF!" pretty quickly.
You almost can't kill a silver can motor, but you can definitely kill a black can.
I always motor spray my silver can motors after each heat...it's never seemed to hurt them. I spray them out with air, then hose them down with spray...let it dry, then a drop of oil in each bushing and one on the comm and go race again. I'm no expert, but it seems to run fine.