Going brown to platinum

I'm actually a licenced professional, but I SUCK at color removal and correction. I originally had blue/purple hair. After using a color remover, I now have orange/brown hair. I need to go platinum because I'm doing a blue/silver combo. I need this Orange OUT. I used a toner, so it's not brassy anymore, but I need it significantly lighter. I'm probably going to do a soap cap (my hair is generally healthy. Not dried out at all) But if it's still orange AFTER I lighten and tone it, what do I do??