Danger in patination?

I use Jax-Black to patinate my (base metal) jewelry. For a
wide-band ring, I dip the whole ring and pumice off most of the
darkness. I leave a little on the inside of the ring to (hopefully)
slow the process of tarnish getting on the wearer’s finger in humid

My question is about whether the selenious acid which is in the
Jax-Black leaves any kind of residue which could react with bare
skin and perhaps migrate through it, causing potential problems,
since selenious acid is poisonous. I’ve been wearing one of my own
rings and haven’t noticed any problems, but one never knows!

Does anyone have any hard on this? Thanks in advance!

Judy Bjorkman