How to ween my 21 month old son off the pacifier?

I have a 21 month old son that only uses the pacifier at nap time and bedtime and sometimes when hes really cranky. all of them are starting to crack so instead of going out and buying more i want to ween him off of them all together. i just dont know the best way to do it. i dont want to traumatize him by making him go cold turkey. so im lost please help!!!