You quite often see Audio Technica electronic stylus cleaners coming up on eBay. I've never used one because I've yet to win one, they seem to be very popular and attract a lot of bids, usually between £15 & £20. Maybe one day I'll get one for a tenner 🙂
If you're getting a lot of residue buildup on the stylus tip, you could try drawing a piece of fine abrasive paper (like the side of a matchbox) across the tip in the same direction as a record would flow for a distance of just 2 or 3cm. I know a couple of chaps that rest the tip in a small pool of vodka before doing this and they claim it works. I know this all sounds mad and if you are too concerned about it, maybe somebody else here will have some suggestions. Good luck.