Well you CAN take them apart and replace the contacts. First remove the cover. In the moving pin (center pin of the solenoid) just beneath the contact there is a hole. You can put a small pin in there and then unscrew the bushing with hex top on top.

BUT! often a platsic bushing in the moving contact gets stamped and shrinks a bit causing the moving contact to stick on the pin. That results in not enough spring pressure on the contact and your new contact will burn again soon.

This relay is the SW215 and a contact kit for that will fit.