smudge on inside!!!

hey all, i just bought my 50mm 1.8 lens and a few days later i noticed a tiny smudge on the back glass..... umm.... how do i clean this without getting any scratches on it??

Is it on the inside of the glass (as the title suggests) or rather on the outer surface of the glass?

If the latter, a careful wipe with a clean microfibre lenscloth or lens tissues should do the trick. If it is a stubborn smudge then add a drop of lens cleaning solution onto the cloth/tissue first. Never drop cleaning fluid straight onto the lens though as it may get inside the lens and cause more problems.

You shouldn't scratch the glass if you use decent dedicated cleaning materials.

Sometimes after using cleaning solution you need to do a little careful, light polishing with a dry micro fiber cloth or Lens Pen.

To prevent scratches, in addition to using only clean (new, where appropriate) cleaning materials as Mike suggests, always dust the surface first with a blower or very soft brush to remove any grit. You don't want to rub dust particles around on the surface.

LensPen.

thanks for the advice! i cleaned it and it turned out to be a scratch after the smudge went away!! im so mad right now..... hemmpphhh...... return it to amazon i guess

I wander if people who gave you these advices realize that the coating on the back of the lens if exists is far more fragile and easily damaged that on the front element.

huuh??.......... what coating?