Large scale bottle cleaning ?

[goldencoin]

Hello, i have recently found a huge bottle-dump with at least a hundred complete bottles on top and who knows how many buried( trust me there is altot of ground to cover....I saw a washing machine completly buried except a little was dug up by an animal) The bottles are young on top( 60's, 70's ) But is it old ( there is an old time farm cart around) I plan to sell most on ebay when they start to acumulate value.

There is a ton of hard dirt, even a toothbrush can't get at the tuff stuff. I'm useing water to try an losen it up. Is there something else i can do to speed this up. Any suggestings how to make this operation more effeiciant? any tips for bottle dump digging/

Thanks
-GC