I just bought a used Canon 28-105mm and when I got it in the mail there was some weird shiny substance, possibly like oil, coming out of the focus barrel. Without thinking I wiped it off because at first I thought it was just fingerprints, but then afterwards I realized it was something weird.
I waited a day or so and noticed some more has appeared, it's not around the entire lens like it was before but it's the same shiny substance.
Any ideas what this is? Should I return this lens?
The odd thing is that I had also bought a Canon 50mm f/1.8 and opened it at the same time and it had the same shiny substance on the focus ring, but it hasn't returned. I do live in Arizona and it's currently around 90-100 degrees, the packages were shipped USPS.
Added some photos to show that it could be on the lens elements. When I look inside the lens the side of the lens which I assume are normally black have a red/amber hue to them. Does this change things? I bought the lens on ebay but it was listed as 'excellent' condition.