Originally Posted by fietsbob

since spraying is not getting the de gunking job done,
pull the lever off maybe the plastic-rubber hood too, and soak it in some solvent..

probably must have both cassette and lever same speed number, but ,
cassette driver, part of the hub, may be different.. 9>10.

Since you are in LA, ask at a bike shop that caters to high end race bike users.
probably a dozen in the Metro area..

as below, step 1 is check dropout hanger alignment on the frame..