I've just bought a second-hand Cycle Ops turbo trainer and was wondering how I can clean it and whether or not I need to get it serviced.
I would start by downloading the manual for your model of trainer from https://www.cycleops.com/support/product-manuals
If its the sort of trainer with a cassette and you remove the bike's rear wheel to train, then you'd clean it like a normal wheel/cassette.
If its roller-based and presses on your rear tyre, then there's probably very little that can be done to clean it.
Either way, soapy carwash, a soft brush/sponge, and a gentle shower of water is probably fine. Don't use high pressure on any bearings or seals.
As for servicing, probably only useful if its got a problem like squeaks or graunching under use.