When your adhesive is not closed or stored in optimal conditions, or if the nozzle isn't cleaned / wiped efficiently we can experience expansion of the glue into the lid, leading to a glue nozzle that is covered in gunky nearly cured glue.
Instead of throwing the bottle away or worse, using the chunky glue on your clients, use a Nozzle Remover Tool to remove the ruined nozzle and then replace with these plastic inserts for a like-new adhesive bottle.