[tempestwizz (Brian)]

My canon 15 by 50 is binoculars have a turret that swings open to adjust for width of eyes when viewing. This turret was covered in a black rubbery finish. After having then in a drawer in their case in my tropical location I note that what was a softish rubbery finish has now turned into sticky goo. The goo is like a viscous black mass that adheres to fingers and anything else on contact.
Does anyone have any suggestions as to how to sort this out?
Can it be simply removed with some solvent? Thanks in advance.