Gave a quote today for a lounge carpet which appears to have dried in rock salt on it

Sorry I havnt got a pic, but apparently she had loads of people in her house (funeral) and they all left there shoes on...there seems to be a light haze on her blue, wool carpet.
Anybody came across this ? Could the salt damage the carpet ?
Going back on Thurs...told her there was no guarantee I could remove it

Thanks