A cordless Dremel would be idea here with a steel brush cup bit to clean up some of the deep grooves inside the carb. Unfortunately mine is worthless because the battery just gave up after a couple hours of use.. what a POS. Anyhow this is getting ready to replace the float and needle after the dip. If I worked any harder at removing anymore residue I would probably damage something or wear out the details in the casting. This is nice and adequate.