Alum Block: Public Service Announcement and Question

[pwc123]

I've been using my Bloc Osma Alum Block for a couple of weeks now and I'm happy with the results aside from one thing...

A couple of nights ago I was shaving at a new sink (new to me anyway) that is framed with a marble or granite counter top - I'm not sure specifically what, but it's certainly a natural stone. I left my block to the right of the sink, which I had loosely wrapped in some paper towel, and proceeded to shave which resulted in my slinging of water all over the bathroom just like every other shave. However, this time, when I went to pick up my alum block, now thoroughly soaked in water, I noticed that there was a good amount of residue and the paper towel was sticking to the counter surface more than it would with just plain water. I didn't think much of it. Thought I'd let the counter dry off and soap it down later.

Now, after 48, it's clear to me that I am not going to be able to clean off these marks/stains. There is some discoloration and even the "imprint" from the design of the paper towel which is now ingrained in the surface of the counter top. I did the requisite web searches and saw in a few places that there are warnings about storing alum blocks (or even using one) on marble or granite counters. Shame on me for not knowing in advance. Assuming what doesn't damage my skin won't damage the counter clearly was flawed logic!

My question to you all is can this be fixed? Is there some magic marble cleaner or some sort of buffing I can do to return the counter to its original luster? And what exactly happened? Is it a chemical reaction or did the alum leak/drain in to the pores of the counter?

If nothing can be done, oh well. But I hope that I can help at least one other member avoid a similar fate!

Thanks in advance for the help, guys. Not many other places on the internet one can turn for such advice.

 

[rajagra]

Leaving a damp cloth over it for a looooong time might eventually dissolve it away.
Is it safe to use steam cleaners on such surfaces? I think the heat/moisture would be very effective. My concern would be the risk of cracking it, maybe I'm just paranoid though.

 

[dott_macchia]

Did you take pictures?

 

[pwc123]

Leaving a damp cloth over it for a looooong time might eventually dissolve it away.
Is it safe to use steam cleaners on such surfaces? I think the heat/moisture would be very effective. My concern would be the risk of cracking it, maybe I'm just paranoid though.

Hmm, not sure. Might be worth a shot...Thanks

Did you take pictures?

I haven't and I'm at work. I certainly can late tonight though.

 

[abrowncrayon]

Sprinkle some turmeric on it...the turmeric stain will cover the discolouration with a nice skiffy yellow mark that can't be removed .

I'm afraid I don't know the answer but I hope you find one. I had no idea Alum could do this so thanks for the heads-up.

 

[takeshi]

A lot of natural stone countertops (granite, marble, etc) are porous. It's not just alum that one needs to be worried about with these materials. One reason why we're going with quartz for the kitchen remodel.

 

[luvmysuper]

As we are not there, it's impossible to tell if this is a stain, where the block had an actual chemical reaction with the compounds in the stone, or an etching, which is erosion of chemical compounds in the stone.
If it is a stain, there are commercial poultices you can apply which absorb the material. You have to be very specific about which poultice you use for what type of stain, and on what type of stone.
Read the labels very carefully at a local store that sells granite and marble.
If it is etching, you can use #000 steel wool, with NO water, and a VERY gentle motion to try to buff the area smooth.
Granite counter tops should be resealed every 18 - 24 months to prevent this type of thing.

 

[m139]

I have granite is my kitchen and some bathrooms and marble in others and they are both very different in terms of absorbing chemicals. Even if you seal it, marble is still much more susceptible to staining because it's much more porous than granite. With all this said, I would recommend you have a professional look at it and determine if it's a stain or an etching (i.e. chemical reaction). If a stain, then I'm sorry to say it will be very unlikely that you can get it out because whatever stained it has already penetrated into the deeper layers and from my experience it would be near impossible to get it back to original. If it's etching, then you most likely can take previous advice and buff it out then you must seal the surface again.

 

[pwc123]

Thanks, guys. I'm sure it'll require buffing at a minimum. Second picture is undamaged, first is unfortunately my doing. Mark this one down as a lesson learned. Appreciate everyone's input and suggestions though!

 

[rajagra]

I had always assumed that granite/marble worktops were natural stone that had been carved into shape. But there was a How It's Made show on yesterday that showed how it starts as a mixture that's put into moulds. The marbling comes from mixing in different coloured mixture and stirring it a bit! What a con!

Anyway, the important thing is they finish by using hand/power tools to grind off rough edges and then polish it. So as a last resort you can always sand the surface down and re-polish it.
But don't take my word for it, do some research before you go down this route.

Edit> Found a YT copy of the show http://www.youtube.com/watch?v=M2dXUD9K1Kk but the sound goes off. But it lasts long enough to say this refers to cultured marble. I didn't catch that part when I first watched it.

 

[Slash McCoy]

You need to lap your countertop.

Seriously, maybe rub with .25u diamond paste and a piece of an old tshirt. A little dab will do ya.