Depending on size of handkerchiefs, ie if they are all the same size, you could stuff them with foam fibrefill and make toss cushions, or if they're very small, pincushions, although using them as inlay for glass boxes is also a neat idea. A friend who has sewing machine has made me a whole of cushions, out of pretty fabric napkins, runners, and most recently bright bandanas. Cost - next to nothing! Just a matter of thinking out of the box. Hope this helps.