Hi there;
You can try this stuff its called "Goof off"

I went to the Sanford pen website and looked it up....
here is their website:

http://www.sanfordcorp.com/sanford/consumer/jhtml/help/sanford_help_96.jhtml?_DARGS=/sanford/consumer/jhtml/consumer_stainremovals.jhtml_A&_DAV=Stain%20Removal%20Products#PermanentMarkers


Refer to Concrete or graffiti.
----- Original Message -----
From: "Kimberly Kenney, Curator" <[log in to unmask]>
Date: Friday, October 8, 2004 6:35 am
Subject: removing graffiti

> Hello all,
>
> We have had some vandalism on our site.  Fortunately
> it was not on the McKinley National Memorial itself,
> but rather on a small gazebo behind it.
>
> The gazebo is made of concrete, and the writing was
> done in thick, black permanent marker.
>
> Our maintenance staff has requested that I ask this
> group for a possible cleaning solution.  They have
> already tried acetone and it didn't budge at all.
>
> Thank you for your suggestions!
>
> Kim Kenney
>
>
> =====
> Kimberly A. Kenney, Curator
> Wm. McKinley Presidential Library & Museum
> 800 McKinley Monument Dr. NW
> Canton OH 44708 * 330-455-7043
> Visit the Ohio Memory Project at http://www.ohiomemory.org
> "Let us ever remember that our interests are in concord, not
> conflict; and that our real eminence rests in the victories of
> peace, not those of war."  --25th United States President William
> McKinley
>
>
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