Speck on my lens--help!

[deirdrec]

I just bought a Sigma wide angle multicoated lens filter to protect my new lens from my sons sticky hands. Well, I cleaned it tonight for the first time (he had already made a mess of it) and noticed a small speck that does not seem to come off. It is like a small spot of discoloration (very tiny) that reflects light when viewed under a bright lamp. I usually use my breath and a microfiber cloth to clean but tonight actually used lens cleaner and lens tissue in an attempt to get the speck off. I'm afraid to rub hard. Any ideas? Could this be a manufacturing issue (I got the lens Friday)? Perhaps back to Adorama?

[chinoamigo]

try a lenspen.. i use that to clean all my lenses/filters.

[bubba zanetti]

Any ideas?
Id try a lens pen as suggested, for the cost its a handy thing. My lenses have marks like that which come & go. Dont lose sleep though, its not about to change your photos. (http://www.lensrentals.com/news/2008.10.30/front-element-scratches)