Oxygen Sensor?

I changed my exhaust manifold on my 93 accord LX, but could not remove the oxygen sensor. Should I buy a used one, or just get a new one? If I buy a used one is there a special way that I can clean the sensor without damaging it? Also, does anyone know of any good websites that I can search for the part? The ones I have found have been fairly expensive.

Thanks

I would have a hard time trusting a used O2 sensor. They may be expensive but they last a long time, I'd go new.

billcat is right, get a new one and be done with it.

i rebuilt my 90 accord,had the same problem.(i'm not sugg this) I couldn't get a socket or wrench on it, so i cut it off w/grinder and used a long impact socket and breaker bar---heat and thread solvent are opt---autozone has BOSCH O2 for $95.00(buy a new one)!!!