I used to clean my BSA at a car wash and suggested it to a friend. His motor was still too hot when he hit it with the spray and the contracting cylinder broke one of his pistons. So take your time and let things cool down 1st.
As for Commando cleaning I can cast no stones at Dave.... A wipe with a rag without too much oil & grime, for heavy stuff used mineral spirits/same rags & maybe a brush.... It loves it and thrives in the light to medium layer of hydrocarbons... Perhaps a splash with the garden hose, but never a power washer which can penetrate into places water should never go.
I do however care for my lacquer paint differently.