Genetics and stress cause OCD. The cure is to ignore it. Acknowledge it but do not act on it. The anxiety of not acting on them will slowly diminish. OCD is when your brain has faulty error detection.
It is overactive, so you begin performing odd actions such as washing your hands in a specific way and repeating if you do not perform it perfectly, and incapable of identifying when the action is adequate, so you keep performing it many times or for a period far longer than necessary. You need to acknowledge that you have this problem and know to not indulge in it.

I also think OCD is linked to paranoia. People with OCD have odd ideas of hygiene, food, and other things which are not scientifically supported. They think all germs are dangerous, or that something dangerous is there but that we cannot see it and science has yet to discover it.

Think back to before the OCD began. What changed? Why did you not perform those rituals then? You didn't die or hurt yourself. Nothing happened. You slowly began small rituals, and those grew until it coagulated into a large disorder.

OCD is anxiety and fear from uncertainty. There is nothing wrong with being uncertain. Rarely do things end up going how we planned.