how would you handle?

[Anonymous]

This might be impulsiveness stemming from the ADHD.
Consider whether this is an impulsiveness issue or a stealing issue -- only you will know. To me it sounds like untreated impulsiveness. My kid is actually UNABLE to control impulses at times. You can help by keeping temptations away (lock up jewelry) but the problem would probably show up in other ways.
If ADHD-I is the root, punishment and making the child feel bad will not fix the behavior. They usually know cognitively right from wrong by can't stop themselves.