[shovel]

The PCV valve, (positive crankcase ventilation) pulls vapors out of the crankcase during engine operation so that they don't condense when the engine cools down, into potentially corrosive or solvent substances in your oil.

This results in a longer lasting engine, and longer lasting lubricity of the oil.

I've never heard of a PCV getting yellow gunk on it... maybe from using a paraffin based oil? ( PureBase is the trade name of a paraffin oil from Pennzoil for example)

Frankly I've never had a clogged PCV valve, ever, in any car I've owned. And they should be around 5 bucks, not 30 - or you can probably clean the valve itself with a little solvent. It's just a one way ball valve, nothing fancy.