[michael1]

I have a customer that has white marks on the wall  they look like chalk marks  I hahave asked a builder he said its salt   I cant get them out whith tfr and 3000  psi and a dirtblaster     there was a bush  over the wall for years  could it be sapp  dripping over the wall  neat tfr doesn't even  cut into it        any   products     any advice   I will do it as a prodject  for future 

[Kev Martin]

Its probably efflorescence

[JandS]

What the builder said...it will dry off and go away eventually.

[Darranvps]

Efflorescence as Kevin Martin Said - Get some efflorescence remover from him and only use steam at 150 degrees c so as to not saturate the wall which will only bring out more salt

[JandS]

Just leave it it will go away eventually, usually happens on new build walls.

[michael1]

thanks for the answers  but I don't think its what I need 

[Smurf]

This is an extreme example of what can happen when you  attempt to pressure wash walls down on a house.
I bet that was a bugger to rectify too.