In my 94 accord Lx, I am getting more than allowed CO% when I go for emission. There is no check engine light.
I have already changed plugs, wires and air filter. The guy at the emission station told me that the oxygen sensor may be dirty.
where is it located and what is the best way to remove it and I clean it?

 

There should be one sensor right in front of the engine attached to your exhaust manifold and one under the car right after your catalitic converter. The one that would most likely cause the issue is the one right on the exhaust manifold behind the radiator. If that's not the issue it may also be that your catalytic converter isn't doing it's job fully... However if that were the case I would think that you'd have a check engine light on...

To remove your O2 sensor it's usually easiest to get an O2 socket for a few bucks from an auto store...

 

the o2 sensor is located on the exhaust manifold and is easiest to get off with a o2 wrench. another really good way to have an unclean burn in your motor is to have one or more dirty injectors.....just as an idea

 

Had to replace mine at $352.00 otherwise the gas mileage is really bad. I have a 96 Accord EX-L four door sedan