What does oil/grease actually DO to optical discs?

Question

I used to believe that oil/grease (such as from fingerprint smudges, cooking fumes, and other sources) were detrimental to CDs and DVDs.

However, I recently tried to look into the matter again, and I can't find anything on it anywhere. So now I'm imagining that I created the illusion of an issue in my head.

I mean, I know that oily smudges on the underside of a disc CAN affect playback or recording (although most of the time seems not to), but in terms of the longevity of the disc, does the presence of oil/grease actually make a difference?

I remember reading somewhere way back when about deterioration of the surface material of the discs due to the presence of oils, but now I can't find any information on the subject anywhere.

Is it just a myth, or is it indeed true that oil/grease are actually HARMFUL to the preservation of the data in the discs? Because otherwise, I've just been stressing out over the past few years for nothing.

I've always been paranoid that if I leave a disc out even when someone's cooking something on the stove, that the molecules of oil from the cooking fumes (although trace amounts) will damage the disc in such a way that I won't be able to play it after a short amount of time.

I know it sounds absurd, because even if there were detrimental effects, logically speaking it would take visible amounts of the substance as well as LONG periods of time (I would assume) for any deterioration to occur ... or am I wrong again?

Answer 1

Good question!

Oil, grease....etc block the laser from reading the info which is embedded in the disc. It can come from fingers, surfaces and yes out of the air like you said with cooking, but it would take tiiiiime, and no permanent damage. Washing gently with dishwashing liquid or windex will remove them. I actually run it under the faucet while soaping it. No harm! Dry with  soft tissue, gently rubbing from center to outside of disc. Scratches can only be removed with special equipment which all rental places such as WOW! Video....etc use. No guarantee on success, depending on severity.

Hope this helps.

DW