You will go through many rags during the project.
It is imperative to keep the work area clear of grease, wax, and dust. The best way to accomplish this is to frequently wipe down the project with a CLEAN cloth.
I like tee shirt cloth for this purpose. In the paint supply section of your local hardware store or home center, you will find a "box of T's" for about $20. Pick one up. You'll be glad that you did!
You will also have need for some "lint-free" cloth. This is widely used in applying finishing to woodworking projects. It can be found near the stains aisle. Note that there is a difference between lint-free cloth and tack cloth. DO NOT use tack cloth -- it will get sticky gunk on your work that will have to be cleaned off!
It is important that any cloth that you use be CLEAN. It makes no sense to wipe the wax or oil off of one section of the boat only to redeposit it in another section. Change to clean cloths often!
Some people wash their cloths and rags in the laundry. I haven't found that to be particularly useful.
Go back to Fiberglass Tools from Rags