Cleaning master cylinder reservoir

I've got my master cylinder reservoir off to clean all the black residue out of it. I thought I could get in through the holes in the bottom until I realized how small they were when I got the reservoir off.

Any suggestions on how to get this cleaned out would be appreciated - specifically the chambers at the front and rear that you can't get at through the fill hole due to the baffles. I see in my Chevrolet manual it says to use denatured alcohol.

The thought of using brake cleaner crossed my mind, but I didn't know if that would damage the plastic or not.

use breake cleaner it will not hurt the plastic. brake cleaner is pretty much alcahol and water. it would be really bad if gm made brake parts that would be hurt by brake cleaner. ha ha