Recent treks to the thrift shop turned up a lovely Olympia Splendid 33. Aside from vacuuming out all the dust and bits of rubber erasings it required a minor repair: the carriage was off the lifting arms. This was easily fixed with the aid of a small wrench and a jeweller’s screwdriver. I also treated the platen with a very light coating of silicone lubricant, rubbed on with a rag. Silicone seems to do wonders for platens, but should be used sparingly. This platen now has a perfect grip. It took a few days for the treatment to dry properly however, as at first the rubber was a bit too soft and impressionable – like a lot of people..
olympia splendid 33
I’ve left this machine on my desktop, the real one that is, where from time to time I like to doodle away with random musings – here’s a couple.
nathanguitars 
I hadn’t heard of the silicone treatment before. There’s always something else to learn about typewriters.
I usually treat a hard platen with brake fluid, which makes the outermost layer softer and helps it grip. Sounds like silicone has a similar effect.
Rubbing with Soft Scrub is also great to remove the hard and dirty surface.
I only recently saw this somewhere, too. The brake fluid treatment made some platens too soft, in my testing. So far these results are good, but I expect that it depends on the particularities of what rubber compound is used. I’m testing silicone lube on another platen.