Thank you so much for your comment. Good that smell isn't included here :D
You can try to wipe it clean if it's on the most outer lens. If it's inside of the cam or lens it could be more complicated but if the lens is detachable you could bring it to a camera shop and perhaps they can clean your sensor and/or lens.
It isn't completely clear from your description what the problem could be. Perhaps you could show some example images and post links here.