Keep in mind that usually if a shadow or blush was matte or extremely fine & shimmery it probably wont or will be very difficult to press back together.
To find out what you will need & how to re-press your shadows follow the link below...
In my example I will be using a very popular but broken NARS blush called Orgasm.
What you will need:
-A squeeze or spray bottle filled with 99% Alcohol
-A mixing container
-Q-tip with on end cut off
-A quarter or circular object
-Some sort of weight (Books)
STEP 1: Using the cotton end of your q-tip soak it in alcohol and sanitize your eyeshadow pan.
STEP 2: Empty your broken blush into your mixing container. Add alcohol a bit at a time, mixing in between until powder has turned into a smooth liquid.
STEP 3: Pour liquid blush into the eyeshadow pan. You can use the pan that you took the broken product out of. Just make sure to sanitize.
STEP 4: Make sure to move the product in the pan to ensure there are no air bubbles.
STEP 5: Next you will want to cover your pan with a cloth. Cheese cloth works great... Or something similar to that. Put your quarter on top of the shadow, sandwiching the cloth between the shadow pan and quarter.
STEP 6: Apply weight on top of the pan, cloth, and quarter. I like to let mine sit for a good 24 hours to ensure all the moisture is out.
Once your shadow is dry and rubs off the pan like a regular shadow it's ready!
All very easy to do with house hold items.
You can also use this method to turn loose pigments into pressed for so they can all fit in a palette.
I hope this was helpful. If you have any comments or tips of your own feel free to write below in the comment section.
Peace & Luv