Grease and fingerprints look equally ugly on fashion phones and low-end devices alike. Sony Ericsson have just patented an interesting technology that allows to clean the phone's surface from dust and grease automatically. It works similar to a windshield wiper. As described in the patent, it works for sliders and folders, however no support for the candy bar form factor is stated yet. Unfortunately, the popular touchscreen candy bars seem to be out of question, though they're especially prone to soiling. 

Once you fold or unfold the phone, the wiper moves along the screen surface, removing the grease and fingerprints. If Sony Ericsson find a way not to spoil the phone's looks with adding such an element, it's sure to become popular in the future models. However no information is available on SE's plans to implement it in their upcoming novelties.