A method of reclaiming a well completion brine solution by using an organic chelant that is capable of discriminating between (i) iron and non-zinc heavy metals; and (ii) calcium and zinc. The chelant contains a functional group selected from the group --CO.sub.2H or --PO(OH)R.sup.20 or a salt or ester thereof, --C(O)--, --OE, --SE, --N.dbd.C(R.sup.2)R.sup.3, EO--N.dbd.C(R.sup.2)R.sup.3, --N(R.sup.2)R.sup.3, and --N(C(O)R.sup.1)R.sup.2 group optionally substituted with a --COOH or --PO(OH)R20 or a salt or ester thereof, --SE or --OE group, wherein R.sup.2 and R.sup.3 are independently selected from E or forms, with nitrogen, phosphorous, oxygen or sulfur, a heterocyclic ring; E is R.sup.1 or --H; R.sup.1 is a C.sub.1 C.sub.30 alkyl or aralkyl group or a derivative thereof and R.sup.20 is --OH or R.sup.1.