Thank you all for your replies and advice.
Update:-
I've approached several sealer manufacturers. Their advice is generally similar, although none is able to say with certainty that a given solution will work because we don't know what make of sealer was used. Three makers say the sealer...
I'm hoping someone can give me advice on how to clean rubber tyre skid marks off a freshly laid imprinted concrete drive.
Our neighbour spent a small fortune on having a new drive laid a few weeks a go. Then he went away on holiday. Whilst he was away, some kids thought it was a great idea to...