We went in steps. When it was time to give the binki up, we started with:
1- only allowed while napping
2- only allowed while napping IN BED (binki does NOT leave the house
3- Binki has to go with the garbage man because his wife just had a baby and he needs a binki for his new baby.
Don't ask me why, but it worked. We ceremoniously walked the binki to the trash can in the morning (right before trash pick up) and pulled the can to the curb. We watched the garbage truck come and waved to them out the window.. the kids thought he was waving to say "thank you". They felt as though they helped and saw that binki was going to be put to good use by the garbage man's new baby. LOL
edit- we made sure we did it in the morning, so they had all day to talk about their good deed and got plenty of praise for being such a big boy and so generous!