Cloudy residue in bottles

[West wind]

I've just dug out some 500ml PET bottles that have been stored in a bin liner for a few years. They were cleaned before being stored. They have a cloudy residue on the inside. I tried giving them a wash and it removes some of the residue.

Has anyone had this issue and if so what was the solution?

 

[Clint]

Bleach soak,a good rinse,hot oxi with a vicious brushing out then sanitise. The haze in mine was from slugs etc...the above clean sorted them out.
Long term solution...brew more beer so your bottles are mostly all full.