I bought an NES off of Ebay (yes Arjun the one you suggested) the person said it was broke but needed fixing. I figured it was the 72 pin so I bought the NES for $10. I opened it and it turns out she spilled some shit on the pcb! False advertising! Anyway is there anyway to clean a PCB safely?

There are a number of PCB cleaning products available which wont damage the electronics. Check in your local electronics store - they will have something. It really depends what is spilt, coffee can corrode the copper tracks in no time!

you can put the pcb in a dishwasher and let it dry properly afterwards (2-3 days).. or you can use rubbing alcohol, that'll get just about everything off.