Is clean hair absolutely required for Olaplex #3 to be effective?

The time required to wash, condition, and detangle my hair takes long enough since I have curly/coily hair. I’d like to avoid adding another step by having to wash, then add #3, and then do the rest.

But if putting #3 on hair with product buildup doesn’t allow it to penetrate the hair, then it’s a waste of time and money regardless. How do you guys prefer to use it?