Oily substance on keyboard beneath silicone keyboard cover

Question

When I use cheap silicone keyboard covers, I get a slick, oily residue on the keys beneath the cover.

• This has happened multiple times on two different computers with two different covers
• It happens even when I never remove the cover
• The keys and cover were clean to start with
• It's not that they keys look oily. There is a tangible substance that I can wipe up with a tissue
• It does not happen when I use a non-silicone TPU cover

Questions:

1. What is this stuff?
2. Can it damage the keyboard, or is it safe to just wipe it off occasionally?

Solution

It's polydimethylsiloxane and dimethylsilanediol. Essentially, it's silicone and silicone breakdown products. Exposure to UV light, acids, bacteria, and even oxygen will slowly breakdown the silicone chains.

Comments

[octern]

Thank you! As a bonus, do you know whether it can damage the keycaps or the keyboard mechanism, or is it safe to let it collect and wipe it off occasionally?

[David Schwartz]

Probably not. This is pretty inert stuff. But if the cover was cheaply made, it may have other residues that could harm the keyboard. Personally, I'd switch to a vinyl cover if it's not a cheap, easy to replace keyboard.