Curtains Clip Art How To Shorten Curtains Without Sewing?

How to shorten curtains without sewing? - curtains clip art

I need to shorten the curtain, but it's not about me, I can sew, cut, or in any way altered permanently. I can not even hem them free, they are made of a plastic foreign tissue and shows the pinhole camera, even after the withdrawal of his son.

I tried not on tape (loud), and Bulldog clips (it was terrible, and not when I am about 15 clips). Has anyone other ideas?