A few weeks ago I said that while washing our golden's kong I got black oozy stuff on my hands.
After e-mailing the kong co. and sending them the kong I have an answer. The rubber kong for some reason was reverting to its pre molded state.
They advise against washing in dishwasher and using any strong solvents. If using dishwasher to use cool or warm ( not hot water) and never use heat cycle.
As I wash kongs in sink ,don't know what happened. However, they are sending a replacement kong.
Hope this is a very isolated event.