[marki]

If you want to remove anodising without damaging the part you will have to submerge the part in a solution of sodium carbonate and sodium hydroxide and then place into a solution of nitric acid and sodium fluoride. AlO3 is a tough compound to break down. If you want a recipe PM me but only if you have experience in handling chemicals. Conc HNO3 bites back.

Hard/soft anodising refers to the pore size present in the aluminium oxide (AlO3) layer.

Hard anodising is done at cool temps with about 10% sulfuric acid. It leaves small pores which makes a hard surface but is not good at absorbing dyes if you wish to colour it.

A softer anodise layer can be made by using higher temps and about 15% sulfuric acid solution. This has larger pores and is much better at absorbing coloured dyes at the loss of hardness.

Mark