You might run a search regarding steam cleaning your records. I own a VPI 16.5 and use both steam and disc doctor cleaning fluid. The combination of steam and fluid has worked miracles on many of my used and new records. I have purchased a few records where dirt has been pressed into the vinyl, and nothing seems to make a difference. Most of those recording are from Verve & Rhino. Anyways, give the steam cleaning a shot! I don't think you will be disapointed.
Good Luck!
Good Luck!