Some might recall that I recommended Solvol Bluing Remover to clean up dull, bronzed headers
http://www.ukmonster.co.uk/monster/s...2&postcount=12
It works really well but, at £15 for 150ml, it's not cheap.
Well, in the 'Albie Edition' of Practical Sportsbike, there's also a tip about using Harpic Power Plus to perform the same function. I'd actually heard of this before but never tried it. However, as I've got a bottle jammed behind the u-bend, I thought I'd give it a go.
I can confrm that it's just as effective as the Solvol but at a fraction of the price.
Although my pipes weren't particularly discoloured, I think you can see the 'tide mark' where I used the Harpic up to where the heat shield goes.
The second picture shows the result of the Harpic under the heat shield.
Both products contain hydrochloric acid, which is the active ingredient - it works by removing the oxygen from the oxide. The Harpic contains 9% while the Solvol is between 10 & 25%. Hydrochloric acid is, of course, corrosive but, as long as you neutralise it by rinsing with water, that's not a problem.
So, £10 per 100ml for Solvol against around 53p per 100ml for the Harpic.
Plus the Harpic leaves your exhaust smelling citrusy fresh!