Jackson gets a dummy rash when he is teething because of the buckets of drool, I have tried just about every dummy known to man, but he still gets it, I just rub a bit of Dermaveen or even just a moisuriser like Cetaphil into it every day and it normally clears up. I don't know what dummies you are using, but make sure they have some kind of ventilation holes in the shield to let a bit of air through.