Hello henrie. Sadly you will have to try before you decide to clean the whole button array. Its a bummer that rubber/plastic ages like this. I hope you find a solution. But for now maybe try it on a less useful button so you will know if you should proceed with the cleaning. Cheers
Unfortunately there is nothing that can really solve it.
The only thing that could be wort trying is to either replace them or completely wipe the rubber and accept the loss of lettering.
Hi,
It all depends on storage/placment of the equipment over the years. Most of them do not have problems.
The 90s rubber was not great to begin with. Especially on the portables.
We have seen it also on the 300 series as well.
If you find a solution for printing, please share.
I suceeded solving the problem wiping the sticky coat with a towel soaked it a solvent called “kontakt 60” form kontakt chemie.
In my cases with different products of logitech and one expensive eton receiver only the top coat has been sticky but under this coat was the printed lettering which remained.
But be very careful and tape the surrounding and try first whith an not so important button.