Fingers!

I am terrified and gooshy at the same time. Jackson has discovered his fingers and wants to do nothing but slobber and put them in his mouth. Why be worried? Well, sigh, here it goes: I actually sucked my thumb until I was about 8 years old and I fear that little Jackson may fall into the same habit. It's sweet to watch him and refreshing to see him soothe himself, but I am pretty nervous he'll end up like me. It was a terrible habit to break. I have tried to "exchange" a pacifier for those fingers and he'll have nothing to do with it. Any suggestions for making this happen?