No, you will not “have to do it”. Either they can afford to pay a qualified person to do it, or they can’t. If they can’t afford a more expensive person, they definitely can’t afford to fire you. You are the cheap one.

Think about it: if they put themselves in this situation, they are going to end up cleaning it themselves. “Need money for rent and food”? If you have a crappy minimum wage job, you have the power. Literally no one above you wants to do your work. You can definitely tell them “no”. Do you think there’s some shortage of crappy minimum wage jobs?