Our brand new black slate hearth has been cleaned by an over enthusiastic
family member, using FLASH cleaning spray (an all purpose bathroom/kitchen
cleaner) - one of the more powerful ones at that. Where the spray 'skooshed'
onto the hearth, it's left a mark despite being wiped over straight away.
Could anyone please advise what our best course of action is? We're not sure if
it's stained the slate or if it has etched into the slate. The slate was
pre-sealed but how well and with what I don't know. It is probably slate
from china... and probably not the best quality slate in the world but this
is just a guess. Any advice would be greatly appreciated.