I like to take mine apart every couple of months. What I do is, I wipe all the engine parts with a clean rag. Once I have the bare case(with or without bearings) I clean the whole case with a water based degreaser (simple green works) and a tooth brush. Once its nice and clean I rinse it and soak it with WD-40, I use a lot on the bearings to displace any water left on them. After the WD-40 I let it sit overnight and then I put it together with some ARO. I also reaseal everything
I HATE!! the look of a dirty engin.