How do you “freshen up” white plastic patio chairs if an aerosol spray paint doesn’t stick?
The spray paint doesn’t stick because it’s not designed for plastic. It’s difficult to get adhesion with plastic. If you don’t mind scuffed chairs, you can try sanding the chairs with very fine sandpaper before you paint. This will give the paint a better surface to stick to.
Paints and primers formulated for plastic are also readily available. Wash your chairs with an ammonia-based cleaner and wipe them down before painting. Keep in mind that no paint will return the chairs to their former factory-fresh glory; it will only patch them up for a bit.