Originally Posted by
cyccommute
A few minutes should do. If you want to get the cassette really clean, disassemble it. Even if it's riveted together, you can remove the rivets (grind the head off and punch them out) and clean in between the cogs. You don't need the rivets to put the cassette back on either. Just slide the cogs into place and tighten the lock ring.
It's a partially spidered (Shimano 105) cassette. I don't think I can do that. I think your advice only stands for MTB cassettes with cogs that are riveted together, not spidered road cassettes.