I dont think this has come up before but must affect others so here goes...

A summer of riding with sun cream on my face has turned my helmet straps to a metalic gray, salty, damp gungy mess. No amount of wiping, squeezing or rubbing seems to remove the heavily water resistant build up of sludge within the material - also there must be an easier way? After wearing it, im starting to get skin irritation so need to sort it out.

As far as i can tell the straps are not removable, therefore any technique to dissolve this slime must be compatible with the whole helmet.

Anyone have any good ideas?