oil tank cleaning

[R]

Chemical stripping often involves nothing more than a dunking in hot caustic.
(hot tubbing, same treatment as the iron engine blocks get).

With care, boiling caustic can be kept inside oil tanks if all the exits are sealed off.
Take care, of course.
If kept away from the paint, this can be saved.

Alloy should be kept well away from this treatment, it gets literally eaten.

[john.k]

The stuff sold in hardware shops as sugarsoap is often strong caustic and detergent,and is a simple way of buying caustic soda,if local laws prevent shops from retailing it.The nanny state doesnt want you to have anything effective,just "green" rubbish that doesnt work.By the way,strong alkali s will also etch glass,taking the shiny surface from porcelain.Not to mention taking the shiny surface off you as well.Regards John.

[iansoady]

Actually caustic soda is still widely available from Wilkinsons etc.

If you'd grown up as I did in the pit villages of County Durham and seen some of the horrendous injuries caused by the lack of a "nanny state" maybe you'd be less flippant about genuine health and safety concerns.