The rags at big box stores can be used for staining, but you need to throw them in washer/dryer first to remove all the "fuzzies", no detergent or fabric softener. After this, I've had no issues with fuzzies or fibers unless I cut them down smaller. Another alternative are Makrs stain pads. You cut them down to size you need. I saw Matthew Peech use these and I got some to try out. More expensive, but depending on the size of the piece you are doing, you can cut the pad smaller than they recommend. More pricey than rags at the box stores, but I've never had anything anything left behind on a piece using these.
