Another perspective.
If you intend to use these binoculars, the "skin" may currently be quite slippery. If so, a change may reduce their value for sale, but increase their usability.
My father still uses a pair of binoculars that were passed on to him by his father. My grandfather (who spent the entire war as a stretcher bearer) got his from a deceased French officer, who my grandfather spent some considerable time with in a front lines trench during a continuous bombardment during WW1.
I wonder if the OP's binoculars have a similar history.
By the way, neither my Dad nor my grandfather ever did anything to improve or repair their binoculars.
Matt