Alesis HR-16 rubber keyboard

[Ovations]

Hello there,

I am new to the forum and new into drum machines, and I just bought an Alesis HR-16 and a Korg DDD-1.

The Alesis is almost finished: new LCD inserted (bought from here), cleaned the slide pots from dust, hair and several dead insects, cleaned the upper and lower case, inserted a new battery, re-soldered the 2200 uF capacitor which stood up with long legs and was bent over to fit into the case. Currently the drum keycaps are bleached with hydrogen peroxide but I do not know whether this works out.

Does anybody have an idea how to clean the rubber keymat? It is some kind of brown but it seems I can not get it back to grey. I do not know whether the colouring is from smoking or something else.

Kind regards,

Chris