I agree with what what Alec said, but I'll amplify it a bit. What you are looking for is spray contact cleaner. It is used to clean switch contacts, variable resistors such as volume controls and the speed adjustment potentiometers which you are dealing with. Back when TVs had knobs it was also used to clean TV tuners so it is sometimes called TV tuner cleaner. If you have Radio Shack stores in the UK you can get it there. If not look for electronics stores which sell supplies as well as things likes TVs.
You may have to open the machine to gain access to the control. Spray into the control as you work the knob back and forth.
djblowie wrote:Hi. I recently purchased this JVC turntable on ebay. I was advised it was recently reconditioned and it had a fairly new belt and cartridge (which it did). It was well packed but when I set it up I noticed that 33 was running faster than 45!! I thought I resolved the problem by using the adjustment screws and so gave the seller positive feedback.. it wasn't until I played some records I was familiar with that I realised the speeds were well out. The problem is that if I turn the screw the tiniest amount clockwise it runs too fast, and a fraction anticlockwise, way too slow!! Is there anything I can do? I really like the turntable!! (I was given a full refund BTW).