Any sufficient quantity of dishwashing soap is indistinguishable from magic.
Today it got up around 75 and I scrubbed Dixie's mane and tail. FOUR full scrubbings with a vast amount of Dawn got all the brown gunk out of her mane. Two scrubbings got her tail cleaner, but I need to scrub it again. I'm not as concerned about her tail - I don't feel too guilty washing tails in cold weather.
Dixie's mane was as clean as it'll ever be, but it was still yellowy, so I blue'd it. I put a couple drops of bluing in a gallon of water and dumped it slowly up her neck. That helped, but not quite enough, so I added a good squirt to another gallon and did it again. That got me something like a slightly greenish wet mane, but it dried to a lovely white!
Before (testing spray-on hair color):

After:

I also used up the last of her Suave deep conditioner. Only the best household products for my girl. Gotta remember to pick up another bottle.
No full body shots because the rest of her is still utterly filthy - I'm not willing to drench her in cold water this late in the year. Can I actually brush all the dirt out of a thick winter coat, or should I take my life into my hands and try to vacuum her?
Also, yesterday I trained some of the longer bits of my rose bush into the fence. I had these fantasies of covering my chain link fence with a living wall of red roses. Today Dixie shattered those dreams by eating all the rose bits that were poking through the fence. Le sigh.