When you have dry boogers in your nose you can rinse your nose out using a saline solution or use a Neti Pot to help soften the hard boogers.
The boogers should then more easily come out or at least they do for me.
Sometimes you might have to use the Saline Solution a few times to get the boogers to soften and then use a tissue to help remove the boogers and blow them out.
Using a humidifier in your room can also help keep your boogers from hardening and can also help soften them up as well.
Staying hydrated with plenty of water also helps keep your boogers and mucus soft to prevent them from becoming hard and blow your nose often to keep the boogers from staying in your nose and getting hard.