It depends on whether you are using the kind you buy at the store (cheap and flimsy) or if you are buying cheese cloth from the cheese making supplier. If you buy it from the supplier, just put it in the washing machine. Otherwise, the cheap stuff that you buy at the store should be thrown away.
You can buy very lightweight muslin at the fabric store and use that over and over again. Or very fine tightly woven gauze at the fabric store. That will also work and can be used over and over again.
If you want it to last longer, use a satin stitch on your sewing machine to sew down the edges of several large squares of the fabric. Then it will hold it's shape and not unravel quite as easily.
Tea towels are OK, but they are on the heavy side for ricotta.
Whatever you buy, be sure and wash it in hot water before using it to get the sizing out of it.
Sorry. Yes I'm using it for cheese. Right now I'm using the stuff you get at Walmart and I'm using several layers of it and doing it twice. I liked coffee filters but they were taking way too long. I also ordered some butter muslin but have t tried that yet.
I use the heavier muslin type cheesecloth. So far I have made soft goat cheese. I immediately wash the cheesecloth in natural dishwashing liquid and hot water, in the sink. Rinse several times and in summer hang on the clothesline in the sunshine.