Can't stop leak under sink

[Thumbs]

I've taken off the trap so many times that it now needs replacing. Installed new pvc trap, drain pipe, drain body, pop-up plug and flange. Applied a heavy amount of plumber's putty to flange, lightly sanded rough areas on bottom of sink face, inserted and aligned drain body and snugged up new rubber washer against bottom of sink.
It will not stop dripping from where the washer mates to the sink. Reinstalled a couple of times with same results. All parts are new, Bottom of sink is a little uneven but is twenty years old and use to seal.
What does professional do in these situations, Resurface the bottom of the sink?

 

[Matt30]

I've taken off the trap so many times that it now needs replacing. Installed new pvc trap, drain pipe, drain body, pop-up plug and flange. Applied a heavy amount of plumber's putty to flange, lightly sanded rough areas on bottom of sink face, inserted and aligned drain body and snugged up new rubber washer against bottom of sink.
It will not stop dripping from where the washer mates to the sink. Reinstalled a couple of times with same results. All parts are new, Bottom of sink is a little uneven but is twenty years old and use to seal.
What does professional do in these situations, Resurface the bottom of the sink?

I sometimes put a little bit of pipe dope on the face of the rubber, but most times if it leaks it's because you're using a cheap mechanical drain (like the plastic ones that come with faucets, I throw them away) or you're not tightening the drain enough. Give'er the beans.