Dying Polyester?

[widowspeak.livejournal.com]

Greetings, ladies and gents. I'm a fabric dying novice, and in need of some advice.

My partner has a pair of khaki slacks that have seen better days. The pants themselves are in good structural shape, but they have many stains that are rather ancient. (He used to work for Circuit City Firedog installing TVs and PCs, so he had to crawl under desks and entertainment centers a lot. Thus, stainage.)

I discovered after reading the back of a box of RIT that it says, "Not recommended for 100% polyester, acrylic, etc, etc, etc." Not knowing off the top of my head what the pants were made of, I refrained from purchasing the dye in favor of going home and checking the label. You guessed it: 100% Poly-freakin'-ester. *sigh*

So far, RIT has been the only dye I can find locally. Several searches on Google have yielded mixed results. Some forums say, "Yes, it can be done! You just need SUPER BOILING WATER!" Others say, "Nope, the fibers are basically plastic, so it's a no-go." Still others say, "Yes, you can dye polyester, but you need to use rubbing alcohol in place of water, especially if you're using RIT." (That last bit came from a Cosplay forum, so I guess those folks would know what they're doing. . .)

So. . .which is it? Does anyone on here know how to successfully dye polyester? I know going from light to dark isn't easy in any case, so I was only hoping for a gray-to-charcoal range of color, here. Not sure if that matters, but I figured any information I could give would better aid you guys in answering. Thanks!