Mine does receive a blue stain on the back from one of my pair of blue levi jeans. Will wash it with the pockets out next time to really clean the dye out. Otherwise no the phone hasn't stained from anything.
This is a sure way to get rid of the stain on the phone but be careful, rubbing alcohol destroys adhesive. That is why it is real handy at removing stickers off anything Just wondering if this could effect the bonding of the phone.