Hello fabriciom,

It seems that you've started off improperly. If you want to service (clean or replace) cassette cogs, the freehub portion of the assembly stays with the hub. You need to use chain whip in conjunction with the torque adapter for removing the cassette lock ring. Once you remove the lock ring the cogs will slide off of the freehub assembly.

I would suggest taking the wheel to a bike shop with a qualified mechanic. Perhaps they will show you what to do in the future.