now we are heading towards light at end of tunnel - buy smallest possible quantity of " chail " and in same chamra market see who can make it chemical free, and it stays soft as in chewable.
iss ko dhona hai k chemical bilkuk nikal jai magar hard na ho,. keep half of that qty as original give half for cleaning treatment. after ward submit both for lab test & see how much has been removed and if a 2nd cleaning treatment can bring better result without making it hard.
if this can bring you desired results, ! YOOO ! you know what to do .. ! .. give that treated sample to chew bone maker and ask for result same as sample