Can't get at my bathroom sink cartridge

[surfast]

No idea how to get the cartridge out of this sink handle. Nope don't know the brand. Do I need a special tool to remove the cap, is there a cap? Do I need to unscrew from underneath? Signed confused.

 

[phishfood]

Hold the handle with one hand, and turn the bonnet counterclockwise with the other hand.

 

[Zanne]

If you have trouble getting the bonnet to turn, wrap a hand towel or flexible rubber pot holder around it to protect the finish and you can use a wrench to turn it. They sell some things specifically for plumbing that have a rubber strap that are for turning things without clamping too hard/breaking the, but I've had trouble with them getting a tight enough grip to not slip.

or you can use a bicycle innertube like this guy.
[ame]http://www.youtube.com/watch?v=BXl9HP4ZLa8[/ame]