I've been using this for years and it has not damaged any of my irons. I use distilled water, so I don't know if that makes a difference. I only put about 20 drops of oil in about a 38 fl oz of water with about 1/8 cup of vodka. I use a cleaned out "Dawn" bottle, as it makes no mess when filling the iron and I write "IRON WATER" all over it, so they won't try to wash the dishes with it!! :lol: :lol: