Been metal detecting for about 8-9 months, have a Garrett AT Pro. I mostly hunt for relics in eastern NC, farm fields, old house sites, civil war sites. I usually run in Pro Zero mode, 28 iron descrimation, iron audio off, sensitivity 2 back from all the way. I dig a lot of aluminum trash. If it is a whole can, or almost, I usually know it's junk by the erratic number and a squelchy sound at the beginning and end of the tone. But smaller pieces that ring up 40 to 75 can have a consistent number and seem legit. Any advice on settings or techniques to dig less aluminum?