Plumbing questions

For all the plumbers out there - I have a pump for my kitchen sink to push the water to the sewer line, I am replacing the pump and noticed a build up of oils, grease and slime on the pvc and in the pump. Can you recommend anything to help keep from this from building up in the pump and coating the pvc? We do make every effort to not allow grease, debris and other things from getting in the drain, but after a couple of years there is always a build up. Any recommendations for any thing that wont harm the pipes and the 1950's era sewer line?