I hate creating waste. As you might recall from posts Kitchen Detox and Reusable Replacements, it's important to me to be mindful of what goes into the garbage bin. This is why we use cloth kitchen towels and napkins, totes instead of plastic shopping bags and now these cute little cotton rounds instead of cotton balls or cosmetic rounds. I made 14 so I won't run out. (I can't go longer than 14 days without doing laundry - I'll run out of the socks I like.) I would've made more but I ran out of the thread colors I wanted to use. Make as many or as few as you like. The instructions work for any amount of rounds.
Wash, dry and iron fabric. Find something circular that is just over 3 inches across. I used a drinking glass from Ikea. Trace the form onto a piece of paper and cut out with scissors. Make two or three of these - you may end up needing them. Lay fabric out flat on your cutting mat. Place the paper pattern you just made on a corner of the fabric. Hold in place while you use your rotary cutter to cut out the pattern.
Continue until you have two circles cut out for every cotton round you wish to make. I made 14 rounds so I had to cut out 28 fabric circles. If you accidentally maim your pattern - use one of the backups. When al the needed circles are cut out, take a moment to clean them up. They do not need to be prefect but try to get rid of any jagged edges.
Line up one circle on top of another, with wrong sides facing each other on the inside. Right sides will be facing out. Secure with a pin.
If you have a serger, serge the edges together. I do not have a serger, just a regular sewing machine so I did a little faux serge by selecting the zigzag stitch and sewing off the edge. Use a piece of scrap fabric to try the technique first. Once you get the hang of it, move on to the prepared pieces.
Line up your pinned round so the edge is in line with the middle opening of the presser foot. Sew a few sitches, back stitch a few stitches and go around twice with the zigzag stitch. You want one side of the zigzag to land on the edge of the fabric and one side of the zigzag to land off the edge. Once you've made it around twice, back stitch a few stitches and cut. Repeat until you've gone through all the prepped rounds.
Trim any loose threads.