i'd like to buy my wife a lighter colored silicone case for a new 6S she's about to get from me.. However a couple of yrs ago, i bought her a red leather case for her 5, and within a month or two it became dirty and stained from the denim jeans she wears. I ended up having to buy her a black case to replace it, cos she didn't like the phone looking dirty. I have a blk leather case myself so as to not mix each others phone up, i should get her a non black / dark case... I know she'd probably prefer leather, but silicone will suffice. So do they stain easy with denim and the like ?