If you can spread the crack, a tooth pick is good for getting your glue down in the separation.
Tooth picks can also be used as filler. They are good to use when say a strap button comes out. You can put in a couple of picks, break them off after putting in some glue then they are soft enough to drive with a drill the screw back in to setup a strap button.
― earlnash, Sunday, 27 August 2017 23:56 (five years ago) link