When I decided to get married wearing my mother's old wedding gown, I discovered I needed specialized help in two areas. One was altering the bodice to accommodate my wider chest and shoulders and the second was cleaning the gown, which had 20-year-old champagne stains that had never been touched.
Asking around, I learned that THE most recommended service for both was Stadium Cleaners in the U-District (actually closer to University Village). Now, this was many years ago, mind you, so I suppose things could have changed in the meantime (hence the 3-star rating instead of something higher), however, their reputation is a long-standing one which leads me to believe it's one they would work hard to protect.
I also don't know much about what they charge these days except that back when I needed their services, I was trying hard not to spend a lot of money and I remember not seriously choking over the price. Obviously it's worth enquiring about - but if you're serious about preserving a wedding gown, it ought to be done right, right?
My gown was quite badly stained when I brought it in and even though the stains had gone untreated for more than 20 years, they were able to remove nearly all traces - only one small stain was barely still visible after they were done with it.
Their alteration work on an older style gown was also quite good. There was hardly any seam to work with at all and they managed to find a way to give me the extra room that I needed to make it fit through the upper back. Truly, they seemed to have worked miracles with this dress!
Not only that, but my request was essentially a rush job, given the time that I had to plan for the wedding and the difficulty that I had in locating the dress and they were able to meet my scheduling needs without any causing any scares along the way. Truly a blessing for any bride-to-be!