[nomad]

The key is to sow the area with plenty of steel rubbish,heavy nuts and bolts,even car parts like brake drums,rotors anything that`ll give a false signal.The problem is with ground penetrating radar,could metal sheeting,tin foil sheets,aluminum siding,work?

[Sarisky]

keep in mind the two types of metal – ferrous and non-ferrous.

Ferrous meaning Fe or Iron & steel

Non-ferrous – Aluminum, Brass

The metal detectors can distinguish between the two types

Sheet metal may be enough of an RF shield to mask whatevers underneath, but it may be useful to have several layers of cheap, flat metal to confuse the issue

Pie Tins might be a good choice – Everybody likes pie, so save the tins for a “Reverse Treasure Hunt”