[mariusgmioc]

Hello and forgive my late reply as I was very busy with work lately!

I have been using Ren. Met. Decorroder for years and I can confirm it is an excellent product. It is absolutely safe for healthy metal and much better than any alternatives suggested here.

For example pineapple juice that was recommended by some, is quite effective but it is acidic. Moreover, the acidity and thus, aggresivity depends on the brand used. Coca-cola is even more acidic than pineapple juice and definitely less effective than Ren. Met. Decorroder.

Yes, Ren. Met. Decorroder removes etching because etching IS a form of corrosion. Practically etching is a controlled and selective corrosion of certain areas of the metal surface. It's just that the oxidation is not brown and flaky like rust is but dark grey and in the form of a thin film that covers just some areas of the metal.

So after treating either Wootz Damascus or Pattern Welded Damascus with Decorroder, it must definitely be re-etched to get back its patterning.

The dull grey patination that remains after the treatment with Ren. Met. Decorroder is easily removed with Pre-lim or any other very gentle polish. However, the dull grey patination has a protective role as it prevents the formation of rust for several weeks, so if you decide to remove it, you should apply some kind of protection to the metal immediately afterwards (I normally use Ren. Wax and rarely, mineral oil).

And I tried Ren. Wax on leather with great results. I assume that can also be used as shoe polish, but it will be probably the most expensive shoe polish on the market.