If on shabbos, a disposable plastic tablecloth picks up from the wind and a part of it attaches itself to the glass cup of the neironim (the glass that holds the burning candle), may one pull it off because of the worry that it will catch fire. I should note that the plastic being partially melted is stuck onto the cup so pulling it off would involve tearing it.
Yes, it can be pulled off.
The plastic tablecloth is a keli – a utensil of sorts which is used for a purpose – and therefore it is not mukzeh. It can be pulled off and used – even though part of it will be torn.
If it has melted to the degree that it will not be usable, the tablecloth will be muktzeh, and it should be pulled on using one’s body (such as with one’s teeth). Under such circumstances one can certainly rely on the ruling of the Mishnah Berurah whereby the prohibition of muktzeh does not apply to moving things with one’s body.