Here is a picture.



What I see is an oily surface in the middle of the liquid and when I shake it it turns milky.It has always been crystal clear.

I just saw this and I freaked out.Can anyone guess the cause and if this caused any damage?I'm suspecting 2 causes:

1. I had them in a drawer which has its back very close to a heat radiator but the drawer itself wasn't in contact and I find it very unlikely to be able to heat it more than it should.Also I had them in this place for more than a week and this happened within a day or 2.

2. 1 or 2 days before this happened I, for the first time, opened the bottles out of curiosity to see if I can (thinking to transfer them in small sprayers).I read in a similar thread (About wolf) that this could be an oxidation issue.