Brasso dissolves a small amount of the surface of perspex, and thus does a very good job of removing small scratches from canopies. But it's not the stuff for cleaning canopies.
For propellers, I recommend the various "bug-shifter" sprays sold in motorcycle shops.
Chap in our syndicate swears by "Pledge" (household furniture polish) for the inside of canopies, and it does seem to work.
Oil on the underside, I like using a spray-on-wipe-off "hard surface cleaner", which avoids getting dripped on by your sponge and usually does a better job than soapy water.
G