Dude that sucks man! Any return policies or even PayPal disputage? I would not even try to keep it at all as that guy screwed you over on his ad! It probably won't affect IQ, but I probably wouuldn't be able to live with even a slight imperfection on the optics of a lens, but it's just me.
If you got a "deal," ask for a 10-15% refund. If you paid "full price" and want a perfect version, send it back.
Minor coating marks are not really an issue, at least for people who use their lenses 3 marks at a millimeter each...I would be unhappy but would rather have the lens.
I've picked up an FA*300mm off ebay which turned out to have some damage to the coating which was not mentioned in the ad.
The markings are roughly millimeter wide, there are about 3 of them. I try lens pen on it and they remained.
My question is whether this would affect the image and the resale price and how much?
Any help will be much appreciated!
Lens pen is not always a good remover. Sometimes the best solution is to use distilled water, 2 cups, with one drop of dishwater liquid mixed well. Hold lens downward and wipe with a slightly damp soft cloth. Afterward rinse with distilled water only using same procedure and let it dry lens down. If it does not go away, the coating might be damaged.
I would avoid water/dishwashing liquid combo period.
Just use ECLIPSE lens cleaner or if you can't find it, isopropyl alcohol and a clean swab. No residue will be left behind.
Dishwashing soap is harsh...at least I know it is on paint...
Dishwasher liquid is harsh but not the normal dish soap. I use a drop of "Dawn" in my solution. The target for either "lens cleaner" or isopropyl alcohol is finger prints. Any other contaminants may not react to these solutions. I would try them first. If it works, fine. I clean coated telescope eyepieces with the above solution for years without any damage. Try to remove eyelash mascara from optics with the other stuff is impossible. Someone once sprayed air deodorizer too close to my camera which left contaminant on the front lens. The only solution that worked was my good old distilled water with a small drop of "Dawn". I wash my $4000.00 main telescope mirror using the same solution and never had a problem. The process of soap is to break down the oil and take it away by coating the particles. Isopropyl alcohol dilutes only and one needs to wipe the residue on the lens with a lot more pressure than soap.
There was a thread a while back with someone not able to clean a Sigma 24-60 with the normal lens cleaner, almost give up. He tried my solution and now his lens looks like new. It may not always work, no warranty given here. If you feel afraid of causing damage than see a specialist to get it clean.
Glad it worked out. I had a similar predicament -- only I thought I was to blame for the damage! (Is that worse, or not?)
Anyway, the dilute soap-and-water worked for me too. I was SHOCKED that they were just surface spots that came off so easily. The spots were so much more shiny than the rest of the element that I was certain they were nicks and chips. How could they be so much more reflective, unless they were bare glass?
Just goes to show how good modern anti-reflective coatings are, I guess.