Does the paint for plastic lawn furniture work and what prep?

Mine did years ago and they've made great strides since then. I'd scrub it really well since you can't really hurt plastic and then spray it with the correct type of paint. It'll look great!

give it a good scrub with soap and water making sure to get rid of any moldy spots in the corners. Let dry in the sun for a day or two, then spray with fusion paint. I painted mine all different colors and it looks really cheery.

Clean the chairs and spray paint them with Rustoleums 2X spray paint for plastic.

Yes. Buy spray paint labeled for plastic. I've done several plastic chairs and small outdoor tables.

Last fall clearance we were able to buy a very nice round glass top table for our deck. We had plastic chairs that were a dark green. The table was a mossy green color. I bought a couple cans of Rustoleums 2X paint that works on plastic. Washed the chairs off, let dry a couple hours and painted. They mow match the table. This year we bought some plastic flower pots big and small. My wife wanted color in the yard so more different colors of paint went on them. After all the Oregon rain we have had, everything still looks factory new.

Yes, the spray paints work! Just make sure the furniture is very clean.