Tip for free distilled water: Pour the water in the sump of a dryer through a coffee filter (To siff the fibers) and you have perfect distilled water for the iron!
Almost all black clothing will have shine spots when it is ironed. This can be prevented with a cotton (press) lap. But now you still have a garment with shiny spots and you do not have time to wash it again? Just hang in the shower and a layer of hot water in the tub / or leave a few buckets. The steam they are almost completely gone. After that I gently polish with a new / clean sponge, and there's nothing to see.