I'll untie it before I wash it, right?

Usually people rinse with the ties in, and then with the ties out.

I confess that I usually do no rinsing at all, and remove the rubber bands with blunt scissors just before dumping everything into a washing machine that has been filled with cold water and Synthrapol. Synthrapol is a special detergent (available only from dye suppliers) which makes dye less likely to transfer from one section to another.

It is safest to rinse before removing the ties, but not always necessary, depending on how detailed your design is and how light the lightest parts are.