Illustrator :: Retains Unsavory Namespaces In SVGs / Can't Open Own Export

I've got trouble with a part of a bigger artwork I got from an unknown source in an AI file. It seems that even though it is an Illustrator file, AI retained parts of code from an SVG that contributed to creation of this AI file. When I save the file in Illustrator as an SVG not only it won't render in any browser, but also Illustrator won't open it ("This SVG is Invalid. Validate it before opening."). I am at a loss. I've tried all possible combination of SVG saving options.That is a problematic part of an SVG save:

<?xml version="1.0" encoding="utf-8"?>
<!-- Generator: Adobe Illustrator 17.1.0, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->
<!DOCTYPE svg PUBLIC -//W3C//DTD SVG 1.1//EN URL....
<svg version="1.1" id="Layer_1" xmlns="URL....
width="44.9px" height="44.9px" viewBox="0 0 44.9 44.9" enable-background="new 0 0 44.9 44.9" xml:space="preserve">
[code]....

If you save the above code (that is a direct result of saving from AI) as a plain text file with an SVG extension Illustrator won't open it.
 
I have found that opening it in Inkscape and saving as Plain SVG (getting rid of sodipodi and inkscape namespaces) makes it readable again, but for all sorts of reasons I need Illustrator to be able to deal with it on its own.
 
Is there any way for Illustrator to "forget" the non-standard code from placed/opened SVGs? I've tried copy&paste, export as PDF... nothing. Maybe a script?