I will second (pdq)'s recommendation of a record cleaning machine. I have a VPI, and it has made a tremendous improvement in the sound of my record collection. Even ex-library and junk-store records often can be returned to close-to-new quality.

However, they are almost prohibitively expensive -- the least costly VPI sells for about $500, and others go up from there. But if you have a large collection, it may make sense, if you can afford it.

If a machine is not an option, consider using one of the record-wash fluids from either Disc Doctor or Record Research -- brush the fluid into the grooves to release the crud, and then flush it out with distilled water. Dry with a lint-free cloth, or air-dry in a dish drainer rack. Google "disc doctor" and "record research" to find dealers in the UK.

As for Fred's problem of the stylus "sticking," you might want to try using a soft artist's brush and some isopropyl alcohol to clean the stylus -- very gently -- to remove accumulated crud, and maybe increase the tracking force just a bit. Or find a new cartirdge that has an attached brush (such as the Stanton 681EEE) that will remove loose debris before the needle passes over. Consider that the noise you pick up on your digital transfers will stay with the sound every time you play them, so it makes sense to do whatever you can to make as clean a copy as possible.