Why do vinyls skip ?

juxt wrote:if i cant see anything in the groove i do this .I place the needle ahead of where it skips then backspin the record to where it skips. I'll repeat that a couple times -If that doesnt work I scratch on the record where it skips. I just do whatever to f*ck around with it to knock a small dirt out the groove. This doesn't usually work, if it doesnt work after a minutes, give up, and try scratching the groove where it skips with your finger nail.