CDS

I have tried making CDS as Dr. Kalcker advises, BUT i have found the CDS attacks the rubber sealing ring on the Mason jar. Also, replacement rubber sealing rings are readily available, BUT they all seem to be silicone rubber, which is the worst one re CDS resistance. Anyone got a solution? If rubber is broken down, I'm  thinking there is a good chance that carcinogens could leach into the CDS.

Silicone seals are compatible with chlorine dioxide gas (CLO2) and CDS. Silicone will stain as long as it is in contact with CLO2 gas and CDS. When not exposed to CLO2 gas or CDS, the yellow color in the silicone seal will eventually leave silicone. 

The seal on your jar is most likely made from natural rubber and that rubber will be attacked by CLO2.