Errr....I know the premise. I've never personally done it. It is, ah rather involved, and much better explained by a good goldfish book. There's one huge manual out there called "The Manual of Goldfish Health" or something like that (it has a huge oranda on the cover), that has everying (I mean -everything-) you'd want to know about goldfish. I'm asking for it next birthday ;D
But in all likely cases, goldfish will not breed in the home aquarium, so you don't have to worry about hundreds of little goldfishies swimming around the way you would with livebearers. Nor would you have to worry about eggs. Goldfish that do not breed simply reabsorb the eggs in their bodies, and the female releases long, kinky, stringy white fecal matter that is the left-over eggs. It should detach easily, and not be retained on the fish more than thirty minutes or so. Sometimes white stringy fecal material can indicate illness. It's hard to tell which it is unless you're one hundred precent sure you've got healthy goldfish.
~~Colesea