'Detoxes' as we've come to know them aren't a real thing. Your body detoxes itself.
Smoothies/juices/teas are good for extra micronutrients that help your body function (thus helping your organs cleanse your body), but that's not what detoxes claim.

Scrapping your usual food intake for teas/juices etc exclusively doesn't really do much besides reducing calorie intake. This will make you lose weight but that's not cz your body is 'cleansed'. That weight might also come back pretty quick cz calorie deficits slow metabolism

If you want your body to do better at detoxing itself, stay away from overly processed foods and ADD micronutrients to your diet in the form of teas/juices if you like.

I'm a fan of intermittent fasting but, this also doesn't detox your body. When your body isn't using all it's energy on digestion, it can concentrate on other bodily functions. It's ok to occasionally give your body a break but the current concept of detoxing is just inaccurate

Again, teas and juices can help you expel more urine and have more frequent bowel movements, but you don't have to stop eating for them to work and they should be a part everyday life because your body is always cleansing

Some light reading

https://www.theguardian.com/lifeandstyle/2014/dec/05/detox-myth-health-diet-science-ignorance
https://www.health.harvard.edu/staying-healthy/the-dubious-practice-of-detox