I am not sure you want to do either of those, but I would be more
comfortable with hydrogen peroxide than sodium hypochlorite.

Can you rephotograph it with a suitable blue filter, and make a print from
that? Look at it through various blue filters and see. If it is Windex(R),
you might need a cyan filter.

I have an interesting idea:

Start with a nice 35mm negative, scan into computer at high resolution.
Process using Photoshop or other similar tools.
Use Dan Burkholder's process to create an 8x10 inkjet negative.
Contact print onto standard photo paper.

Pros:

1) Being able to perform some magic and still get a permanent print.
2) Being able to print a colour negative or slide without needing
special paper.
3) It's easier to do dodging and burning within PS then with a
traditional enlarger.

Cons:
You have the inkjet negative which costs a fortune to make....

Comments?

  Have you tried washing the print?  It may be the dye is
water soluble and will wash out. A 5 or 10 minute wash will
not hurt the paper. Dry it as you would a new print on
baryta. Its also possible that a sodium sulfite solution
like Kodak Hypo Clearing Agent will either remove the dye or
decolorize it. This also will do no harm to the print and
can be combined with washing it.
  Another possibility is that the dye is not acid fast. You
can probably test this directly by putting some stop bath
into a sample of the window cleaner. If it works soak the
print in water for a few minutes and then treat it in stop
bath. Then wash for 10 minutes. This is again harmless.
  If that doesn't work I suggest first making a test by
staining some plain writing paper with the window cleaner
and finding out what will bleach it. I have no idea what the
dye is so can't suggest a specific treatment. Since the
photo is evidently valuable I am reluctant to suggest any
bleaching method although there are some which will remove
dye stains. They require redeveloping the image.
  Do _not_ use houshold bleach on the print, it will remove
the emulsion completely!