I've tried this with chocolate chip cookies and it worked, but only for that specific brand of cookies. I think it's because my mind remembered that box very clearly, so a lot of the disgust became associated with it and now the actual cookies. If someone wants to try it, try to avoid this mistake.
Also, spitting it out is not enough. You have to actively feel disgust as you are looking, smelling, touching, and tasting the cookie. "Oh my god, looks like squishy it is. Looks like shit. Argh, that nauseating fake-sugary smell is so disgusting. Do I want a bite? Oh god, no, how revolting. I'm about to puke." I'd go through that for each cookie in the box (about 2 dozen), then crumble it in my fingers, and throw it in the trashcan.