(2 Pack) Premium Organic Cotton Cheesecloth Bags for Straining Almond Milk, Yogurt, Juice -Extra Large 14"x12" Suorou Nut Milk Bag - Reusable Fine Mesh Cloth Strainer with Easy Open Drawstring

Q: Will these fit over the mouth of a mason jar?

Yes. It will fit over the mouth of a mason jar that is 4.5 inches wide or 12cm.

Q: How to clean after use? Dishwasher or washer safe? Is it lint free?

It is lint free. I believe hot water would cause it to shrink. It's washer safe on warm or cold cycle. I've also hand washed in the kitchen sink in warm water right after use because the fabric is tightly woven, which creates a smooth surface so substances don't get caught in the threads and are easily washed away.