actually it's to wet the wood in a good harp and there's something about beer that does it really really well it sure makes them sound sweet
I have an old chromatic that's probably at least over 40 years old it was given to me as a gift by an old man that took a shine to me and he was the one that told me about the beer so I'll drop it in a glass of beer, give it a rinse after it sets for a while.....blow it out and start rippin'
I've had quite a few musicians try to buy it off of me or try to trade for it....
when I think back.....it was Johnny Cash that inspired me to pick one up and really give it a whirl though my uncle started me with one when I was about 5 or 6