In the USA the Fourth of July is a big event. I know everyone will have a barbeque on one day or another to celebrate the fourth. Paper picnic goods are an easy way to clean up but they are horrible for the environment. There are so many things the we use at a picnic that can be made from fabric and used over and over again without adding to the landfill. If you ever watch someone with corn on the cob and a messy hamburger, they are probably going to use at least two paper napkins... at a minimum just for the meal, not counting desert. A fabric napkin can be much more absorbent and large enough to do the job no matter how messy the meal is... and lets face it a good barbeque meal is messy! Just supply a bucket of soapy water for the cloth napkins to be disposed of when the plates are cleared so the napkins start the soaking process and come clean when you run them through the washer. There are so many festive patriotic or fireworks fabrics available, the napkins will add to the decorations as well as being a useful, appreciated part of the party... and they are a simple project to make... maybe even one you can teach the kids to do while you do the cooking.
If you don't want the kids on the sewing machine without you, round off the corners on a square of fabric and have them sew a hand sewn rolled hem to create cloth napkins.