Originally Posted by
Amt0571
Unless you spray it directly at the hub seals I wouldn't worry all that much. I'd be more worried about spraying the brake surface (rim or disc).
I usually put a rag behind the cassette when I spray degreaser on it.
The best way to clean a cassette is to disassemble it though. I do that twice a year.
When I really need to clean my disc brakes it works well. but then you have to bed in your pads again. but its easier then sanding.