I have an A/c Compressor, its been sitting around for a few years now and I would lie to re-install it back onto the car.

The pulley spins freely as usual but to turn the actual compressor there is a little bit of resistance. Is this normal, does the internal of the compressor cause this resistance?

Or is it not normal? dirt, grease & grime have made it harder to spin freely.

Should I get it reconditioned/cleaned out anyway?

I've never dealt with compressors before so bare with me, I know its hard to diagnose over the net, any information is appreciated.