I asked the B5 guys but no one really gave me a clear answer and I want to install them tomorrow.

Should I clean the used O2's before I install them? If yes what method?

I found this online but not too sure I would feel OK with blasting them with a torch. I was thinking more a solvent.

How about Seafoam, MAF cleaner or carb/choke cleaner?

Determining ways to clean oxygen sensor raises a basic question: Will the cleaned oxygen sensor be any good to work properly? Since the oxygen sensor is exposed to high heat in the exhaust system to the car, the main contaminant likely to be present is a thick layer of baked carbon on the sensor tip, which doesn't dissolve easily in any solvents. So one way to clean O2 sensor with this carbon deposit is to heat the oxygen sensor tip with a blow torch (like propane). Expose the sensor tip to the torch till it's about to turn red, then dip the sensor tip quickly into water followed by cleaning the tip by blowing compressed air. This will make the carbon deposit to break free. We recommend repeating the procedure a few times until the carbon deposits are removed from the sensor tip.

Another way to clean the oxygen sensor is by using CRC brand QD electronic cleaner to remove fuel and oil contaminants. It's a special cleaner and doesn't leave any residue on drying. Keep a safe distance between the sensor and cleaner nozzle when spraying the cleaner on the sensor and wear gloves and safety goggles to prevent the cleaner from affecting your hand and eyes.

ps. I got a great deal on used O2's/EGT's so thats why I am using used ones.

 

You can also test them....voltage will change with temp. If you don't get .9v, dump it.

 

I am guessing I can heat them up with the torch outside the car and test with a meter?

 

Buy new O2's.

 

I was originally going to get the EGT but I asked if he had the O2's and he did so I figured why not try them.

i don't mind wrenching so if they go bad whatever.

 

The heater circuit is simply tested for continuity..you want to test the actual 02 circuit. Generally the black wire to ground on the sensor. The two white wires are the heater circuit...used to heat up the 02 sensor during warm up to rapidly get the engine into closed-circuit operation.