Aye I've heard of using a hairdrier or a heat gun to bring the panels back to something like, another reason they get the 'crease' marks is that they are pretty flimsy, and can flex whilst tanking it on the road, when I bought my new panels, I stiffened them by lining the inside of them with the aluminium heatproof sheeting you can buy on ebay, as they are an aluminium film put on to a thin fibre glass backing, stiffened them up no end.