Copper's used to get bad in the spring and early summer, I think it was allergies. Anyway I use chamomile tea bags steaped in warm water. Then I let it sit on the gunk for a little bit and use the tea bag to gently wipe them. I worked really well for me and is completely natural. good luck
__________________ My  belongs to Copper and Maddie Mae RIP Sweet Rocky Mommy misses you |