Dig a 1m deep, 5m long trench in your garden with pickaxe and spade. I guarantee you that you won't have the slightest trace of a fingerprint on both hands for

Dig a 1m deep, 5m long trench in your garden with pickaxe and spade. I guarantee you that you won't have the slightest trace of a fingerprint on both hands for quite a while. Given the number of people working regularly with such tools, that's quite a sizeable number of smooth hands :)