My daughter (5) has a beautiful, dark navy-blue wool Rothschild coat (we call it the Madeline Coat) that she loves. She's getting too big for it and I've given up trying to find a bigger one (even on ebay). I've made enough clothes for her to know I can re-create the coat myself, but I couldn't find a source of wool that felt right...until recently, when I found some wool blankets that are just about perfect. They're 80% wool and 20% "man-made fiber" - whatever that means. The problem is that they're RED - great big, screaming, holy-crap-you-gotta-be-kidding-me RED. The kind of RED you can't just dye to a dark navy blue. So here's the question: Can I bleach or otherwise remove the color from this stuff, so that I can THEN dye in the darker color?

Discharging dye from wool is not likely to be successful, and it involves some rather nasty chemicals, possibly even worse than chlorine bleach. Regular chlorine bleach would destroy the wool. ProChem has instructions for "Bleaching Wool using Hydrogen Peroxide", but I suspect that your red dye might resist this process. Many dyes cannot be discharged at all. You could ask for a test scrap before buying the wool, or purchase a quarter of a yard, and try the process to see if it works.

You should, however, be able to overdye the red to a very dark purple or black. You just need to use a lot of dye. For wool, I recommend the Lanaset black, also sold under the brand names of Sabraset and Telana. To counter the red, you might want to mix green in with the black, but in any case, use a lot of dye.

The "man made fiber" might be nylon, which can be dyed exactly like wool, or polyester or acetate, which cannot.

It is a much better idea to dye wool before sewing, rather than afterwards, as shrinkage is likely to be an issue. For ease in handling, you could cut out the general shapes of the pattern pieces, if you allow enough extra to make up for shrinkage. You must also be careful to avoid excessive agitation and sudden temperature changes, as these can cause the wool to felt.

Lanaset/Sabraset dye can be purchased from Pro Chemical and Dye, as well as other dye companies. Follow their instructions for "Immersion Dyeing using Sabraset/Lanaset Dyes". You can buy the other chemicals required from the same company from which you purchase your dye.