unconventional uses of low level spells.

[TuggyNE]

Acid typically bipasses all hardness on objects unless the object has a specific property to deal with that.

I don't believe that's the case. Hardness and Energy Attacks, combined, indicate that sonic and acid do normal damage (with hardness subtracted, if applicable), and other types do half or quarter damage (before hardness is subtracted). Certainly it could be clearer, but there's no specific language saying that acid and sonic ignore hardness, only that they are not reduced prior to that.