I hear this is good to keep the rodent out of the airbox and the naphtha can help the engine run well(?) Could the mothballs ruin a MAF? Any experience here?
I have done this to many of "my customer's" cars that aren't driven much. I put them in the engine compartment away from super hot things like exhaust obviously.
No ill-effects to MAF here. I have put them on the dirty side of the air filter, so they don't get sucked up.
Mothballs are generally a chlorinated aromatic and/or naphthlene. They sublime (go from a solid to a vapor). Rodents rend to hate these and they make an effective way of keeping rabbits away from garden plants.