How to clean Gotta Groat???

Is the following recognisable for someone?
Those black marks on the gotta groat…!
See picture…

How do you get it of? Tried bleach in a spray , tried soap and a hard brush but no help
Any help or tips are very welcome
Regards C

I normally use "ACE spray bleach" the only place I have found it is Carrefour, because it sprays a foam it won't just run down the wall, it soaks into the dirt then just use a stiff nail brush on it.

Never heard it called that before

Should get rid of those pigeons they make such a mess

Have you tried jetting from your balcony and or use aqua fuerte.

Try diluting Ague Fuerta with water this will clean it off but be careful it is an acid so where rubber gloves and don’t let it get onto your plants.
But it will def remove the black,
Hope that’s of some help.
PS you can buy Ague Fuerta in Mercadona it’s in a black plastic bottle in the cleaning fluids dept.

Graham_Lynn wrote::text-lol:
Never heard it called that before

Thanks to all
Regards C