I have a bathing suit that's quickly losing its color, and I wanted to dye it back to it's original color. The tag is no longer on the garment, but I'm guessing that it's nylon/lycra. What type of dye can I use for this? I read a little on your site and it seems that I should use a cold water dye. I would appreciate your help.

Cold water dyes are the best thing around for cotton and other plant fibers, but acid dye is a better choice for nylon. Although all-purpose dye, such as Rit or Tintex brand dye, is poor for use on cotton, it contains acid dye which often works fine on nylon. Alternatively, you could look into mail-ordering an acid dye or Lanaset dye from a company such as ProChem. Use water that is as hot as you think the garment will withstand, and soak it for a long time, but be very careful not to twist or stretch anything that contains lycra while it is hot.