Geektastic: Is it efflorescence from the building materials? Happens sometimes with concrete, brick etc. It's salts crystallising.

You can get cleaner for it from building supplies shops.

I don't know - That is why I thought I would ask the Brains Trust here on GZ.

Yup, it looks like efflorescence. I've had it on concrete blocks. Not sure if it's treatable, I used to just brush it off and forget about it until it came back.

It has to be Aliens 

Soylent White !

Cancer. Don't breathe it!

So much for the Brains Trust.

@Rikkitic we nailed it, it's Aliens it is always Aliens, never Lupus. So one for the train bust 😃

Bananabob:

 

Any ideas what this white stuff on walls is and ho to eradicate it?

 

Holy Cr@p , You might have discovered a rare Peruvian Cocaine Rock... scrape it off and take it down to your local night club, apparently there are people who will pay top dollar for this stuff....

On the other hand it might just be Efflorescence... :)

Its ectoplasm - your house is haunted.

I would like to thank you for all your comments. I am sure the the team from Wellington Paranormal will be able to sort this problem out before it grows to large.