https://www.facebook.com/groups/1794856020751839/?multi_permalinks=4308967442674005

A reasonable sounding version of why not to use some of the commonly suggested methods for rejuvenating platens.

If you wish to attempt to lower the Shore A hardness of your typewriter platen temporarily, I would recommend applying a more compatible mixture of xylene (non-polar solvent), Methyl Alcohol and Methyl salicylate (wintergreen oil) in a 3 to 1 to 1 ratio such as is found in the product called Rubber Renue from M.G. Chemicals. All the necessary chemicals are available on Amazon, and you can make it by the litre for pennies compared to the commercial product.