I too have been able to pull goodies from holes with iron, but the one thing that seems to overpower everything is rusty nails IN the ground... that halo effect it produces is just brutal... it will ring strong in the upper VDI range and even have a strong grouping of positive signagraph bars more so then ferrous bars and can be quite the lil bugger. The sound is what keys me into em, they ring strong on the positive but have that "sputter" mixed in which gives em away. That mixing of VDI numbers can be confusing at times too, I pulled 4 wheaties out of a foundation site yesterday that all rang in the high 50's because of the overwhelming amount of iron close by... The 4x6" DD really helps along with a high recovery rate, but you sacrifice depth with these 2 items, those wheaties were all around 4"... any deeper and I would have probably missed em... The DFX is powerful for sure and a good iron masker but I'm sure I'm missing things still.... only way to know is to dig it all and in heavily rooted ground, no thanks lol.