I've noticed that after kneading, coloring and modeling my MMF tends to get sort of leathery-looking and doesn't bend as well. It just of breaks apart and looks like old play-doh. Am I doing something wrong? Is there something I can add to the MMF to make it pliable again?

This happens to me all the time.. The longer it sets the more leathery it gets.. I just pop in the microwave for a few mins and work with it fast.. It works good for me.. GOOD LUCK

Microwave to make it soft and then knead in some Crisco in small amounts until it feels right. I have MMF that is months old and hard as a rock however when I do this it's almost like fresh made. Mind you I wouldn't use this older stuff for large pieces or for covering a cake just wante to illustrate that the Crisco trick works!

Edit: Also should add that this seems to work with fondant as well. I always colour too much or have extra so they go into little baggies and twisted up tight. If it's dry I just dip my fingertips in some Crisco (that I have taken out of the tub to avoid contamination) and work it in.

Awesome. Thanks!