I did some googling and found this method to re-pack smashed blush back to its original state.
- broken blush / bronzer / pressed powder (basically anything that is meant to be but is no longer 'pressed')
- stick-type object (I used a nail stick pusher thingy)
- isopropyl that is 70%-100% alcohol (or rubbing alcohol if you can't get it)
- tissue / paper towels
Ok the reason why I said use 70%-100% isopropyl alcohol if you can get it is because it has a higher alcohol content. Rubbing alcohol (Isocol is the main brand we have here in Aus) can have up to 50% water. I used rubbing alcohol the first time I did this and the blush crumbled again not longer after. I suspect this is due to the water content - I'm sure someone science-y can explain it.
Ok this is going to seem instinctively wrong but just trust me. Get whatever stick you've chosen and smash up the blush until it is literally all loose powder. Do it.
Add the isopropyl to the powder til you get a consistency like this...
At this point you are wondering what the fck you have done and you're trying to work out how to Ctrl-Z. Bear with me...
Once all the powder is integrated into the paste start to flatten it back into the tin and smooth down the top
Blot blot blot. Use tissue or paper towels to start blotting the mixture. You'll get some colour come off but this is normal. I used paper towels with a pattern embossed into them to give the blush an embossed finish.
Let air dry for some time. I'm not sure how long exactly but you'll be able to tell when it's usable again. Ta-da
(PS I cleaned the excess blush off the rim because I'm neurotic like that).