Black limestone - unusual stain - Stubborn stain removal

[hlcpaving]

Hi

I have black limestone paving slabs in my garden. On bonfire night last year we had sparklers in the garden and when they had exstinguished I put the sparkles in a metal watering can (filled with a small quantity of water). I left the watering can and its contents overnight. When i came to discard the sparklers the next morning there was a thick white material in the bottom of the watering can and a white ring under the watering can on the black limestone paving.

I simply cannot shift the white ring from the paving slap. So far I have tried:

- white spirit
- jeyes fluid patio cleaner
- bleach
- brillo bad
- washing up liquid

Can anyone suggest a solution?

Thank you in advance.

[seanandruby]

try

[seanandruby]

Sounds like sulfur staining from the burn off of the sulfuric acid caused by the saltpeter in the fireworks. If it has burned, or pitted the slab then only one way to go....replace. try rubbing oil on a tiny bit of it to clean it.

[RAPressureWashing]

Stains on Limestone can be a nightmare, if you want you are now to far from me (I think) email me some contact details and I'll get over and have a look, but no matter what you use to remove the stain it will turn that slab back to grey so you would have to re-seal with a colour enhanced sealer to get it back to black.

[Carberry]

Post a photo but if it's 1 slab you might be better just lifting and replacing.

[hlcpaving]

Thanks everyone. I will post a pic tomorrow. Will try rubbing oil into it too - what kind of oil though???