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White spots on lab bench - (Jun/03/2010 )

Hello everyone,

So i'm a bit of a clean freak and I just started at a new lab and there are these unidentifiable white, powdery looking stain on my new lab bench top.I tried cleaning it with 70% ethanol, 100% isopropanol, soap, water, but no luck. is there any solution out there that can get rid of this stain?

thanks in advance



Is it a salt? did you try to warm up some detergent?


why not trying 10% sodium hypochlorite ???
i have seen such spots on our bench,,
and the hypochlorite worked fine ...

think they are salt ...


or some remains of a bagel someone ate in the lab, i.e. flour


10% bleach did not work :P

i think they are stains rather than some form of a salt precipitate.........any effective chemical that might help with the removal of stains out there???

thanks in advance



How about a solution of HCl and two pairs of gloves, worn one over the other.

I used that to clean the counter top of the chemical room in my new lab. Similar to yourself, I had a counter top covered in something that didn't quite go with either hot water or 70% ethanol.


oh I know, I know, use a benchcoat and they will disappear :P


thanks for the suggestion, but i am looking to permanently solve this case so i can clean up any future mystery spots i am destined to encounter!!

HCl did not work either,,,, is there anything in the world that can get rid of this thing??


Assuming you have the standard black soapstone countertops, a fine grit sandpaper should work nicely, followed by several wipe downs with wet paper towel to get all the dust. I had to do this when moving into lab space that hadn't been used in about a decade.


Try pure acetone with maybe 2% water. It might work. Else, try phenol or NaOH. This is all I use to clean.

If you got vim cleaners, try it. It works for me too.

Watch this:

-adrian kohsf-