Great answers and picture, mass plumber, but how do you remove the cartridge? A screw head is shown about 3/4 inch to the right and slightly below the cartridge shaft. Does this screw have to be removed to replace/clean to get at the cartridge. Also, in my case there is still a very slight drip, apparently from the hot water side. but if I can clean and/or replace the cartridge, it may not be too messy.