What can be on a cd that.....

I have some old cds that have been through the mill. Marks all over them. Scuff marks, you name it. They play without a skip, glitch, nothing. Then I can play a brand spanking new cd and after a little skip, jump,--looking at the cd: Nothing. Playing it back the second time after blowing some air on it. No problem. What types of things are on cds that can cause a skip, but not be permanant to the cd? Can, merely, a dust particle or the like, cause a sound effect? I hope I'm making this clear. thanks in advance. peace, warren
If the CD has any unevenness to it may cause the CDP to miss read the info.
Aritificial scratches doesn't always factures the trajectory of the laser. And, dust particles can cause skips. I always blow on my CDs or DVDs if it doesn't read the first time around.
In general scratches, fingerprints and/or marks on CD have much larger impact on playback than same on vinyl. In your deck scratched and marked CD plays but on another might not. If somehow the brand-new CD does not play in your deck it means it has a deffect and needs to be changed.