Have you tried any firming lotions? If you know that this is just sagging skin, then a firming lotion might be your best bet.
I also have "wings" which contain very little fat. I have tried butterfly exercises, rowing machines, chest presses, and other similar exercises. Nothing has worked for me yet.
I can sympathize with you...I won't wear sleeveless, strapless or tank top blouses. My shoulders and arms are in good shape...it's just those "wings" that prevent me from being comfortable in skimpier tops.
Good Luck!