We manufacture a machine and sump cleaner to do that job. With the cleaner diluted to the specifications on the label, add to the sump and let the machine run for 15 to 20 minutes, and then drain sump. Wipe sidewalls of sump, with cleaner and under table if you can. Put new lubricant in and run machine. The new lubricant will also do some cleaning, so be prepared to clean again in a week. We also manufacture oil absorbent pillows and booms which will help keep your sump clean.
If all of these steps have been tried and you still have problems, there could be other issues that will need to be examined. Please contact us.