I do not think that body has self-cleaning mechanism under specific circumstances. For example, body cannot heal from excessive plasma homocystine problem. You need vitamins and supplements to deal with toxic plasma homocystine levels.
Mostly, yes. The idea that detox teas or juices flush out “toxins” is a myth. Your liver, kidneys, and skin already do that naturally. However, eating clean, staying hydrated, and avoiding alcohol or processed foods can support these organs.