The lens cleaners for cd players are marginal at best. Changers tend to not be as vulnerable to dust intrusion as single play units do, but a dusty lens is still a possibility. A waste of $ IMO.

If you want to get really ambitious, pull the changer, remove the covers, and *gently* clean the top surface of the laser pick-up objective lens (the lens should be obvious...) with a cotton swab (I prefer long wooden stick ones with the cotton slightly tufted with a plier to make more gentle, but que-tips work okay too). You have little to loose, and the pick-up lens is pretty tough (but does move in two directions so do be careful).

If that does not restore operation it's replacement time. Pick-up replacement in an Alpine built changer is not economical. I put a USA Audio "universal changer" in my 850t wagon and it works great. But, you'll need to run their cable. I got mine on employee purchase at the shop I moonlight in doing consumer electronic repairs...but I see them on ebay all the time for not much more than I paid. 3 year warranty and what appears to be a JVC changer mechanism. Under the passenger seat I could care less about the brand name...as long as it sounds/works okay and I can control it from my Volvo head unit.

Mail order parts sources that have been mentioned on this board before offer great prices on Volvo changers for the glovebox.