Interesting discussion. It's taken me a very long time to be able to accept compliments, and I think that self-deprecation is used by my ilk because of not wanting to appear self-serving or vain -just in case there's any mistake.
Now when I get a compliment, a sincere thanks and an appreciative smile is enough, as sincerity shows that it means something to me, and the smile is meant as a return gift. I still get abashed, though, and if I really feel the need to say "Oh, it's not all that good," I can always simply rub the back of my neck and look abashed instead. My goofy grin helps.
What got me to start accepting compliments with good grace was when a friend wanted me to record a tune so he could learn it. I did the "humble me" thing and suggested that he could do far better listening to So-and-So's recorded setting of it, whereupon he suggested in turn that I was insulting his taste. That hit home.
On the other hand, I should have told him his taste needed insulting. Some days I'm just so thick.