i don't knwo what kidney clease yoaure doing/ but a grea tmany herbs are not to be mixedor heated in metal..
i mysle fonly use glass pots jsut fo rthe non toxic value
if it says no metla it menas it for a reason.
i woudl sugges tyou og get a glass pot 8)
o rif have a ovenr rpoof glas scaseeole migh t try bringin it to a boil in oven then turning off heat and keep door clsoed til x time ahs passed.
i nmeantime.. get soem visionware off ebay you willahv eto pay a bit for shipping bu twell worht itas a n investmetn on non toxic cookware. also all nylon spatualas etc should be repleced.