Can i do anything to remove a crown that is loose and falling off?

Loose crown: I would get to the dentist asap. If the crown is loose, it may come out and you could swallow it. If the crown comes off completely and you can place it back in easily, there are temporary dental cements you can get at the pharmacy. Don't leave it off for long, the teeth can shift in a matter of days preventing it from fitting.

See a dentist: Go to your dentist, the crown just needs to be recemented, this is easy and doesn't cost very much and only takes a few minutes.

Dental visit: Visit your dentist. There are no reliable techniques to do it yourself without potentially creating more damage. Your dentist can help remove the crown safely and determine the cause of it loosening and if it can be re-cemented or needs replacement.