I search a lot of iron infested trashy sites, areas where digging every single piece of iron just in case I miss something good is just not possible.
In order to have success at iron infested areas you have to use a little discrimination, a small search coil, trust in your metal detector and most importantly trust in your ears.
You may be surprised just how much small iron can be rejected using a minimal amount of discrimination.
Searching small areas slowly from at least two different directions is the best plan of attack, using a slow methodical sweep speed.
No matter how good you think you have searched an area it is possible to miss good targets only searching an area from one single direction.
If you have a VDI screen on your metal detector avoid digging shallow depth gauge targets, both ferrous and non ferrous targets as they have a high probability of being surface junk.
Assuming you are not interested in older iron objects, look for non ferrous targets at depth.
Screen or no screen, listen for feint audio responses from deeply buried non ferrous targets.
Slowly wiggling your search coil over an iffy barely audible target often helps to enhance a deep non ferrous target audio response.
Surface iron and the halo effect of deeper corroding iron help mask non ferrous targets in iron infested areas.
A metal detector will often respond to the corroded iron leaching into the matrix the iron was trapped in.
Small search coils help with target recovery speed if you are using a metal detector not known for a fast target recovery speed.
Target recovery speed is metal detecting lingo for the time it takes your metal detector to detect another target after detecting the last target detected.
The reason for searching across a target rich area from two different directions is to hopefully detect a good target previously over powered by a trash target when your search coil crossed over both targets from the other direction.
You can winkle good targets from areas that at first seem impossible to detect, especially from areas that have previously been searched by hunters using large search coils.
A small size search coil rocks an iron infested area providing openings for methodical hunters, an elliptical shape search coil also helps in areas with known elongated iron obstacles such as pipes.
Sometimes a garden rake or a magnet can be used to clear small surface iron away from a site, or you can just let the beach cleaning tractor do the easy work?
Coins and jewelry in the sand are moved around free of charge at popular beach sites every day, a diamond ring moved a few inches from a corroding bottle cap can make all the difference to a beach hunter.
Of course the main things that will open up iron infested sites are time spent reading your metal detector manual and time spent testing targets so you know how to use your metal detector and know what to listen for.
Take my word for it, the best targets are often hidden in plain sight making them the easiest things to detect if you have a plan to detect them.