Can those liver flush treatments work?

No: They are a scam; you'll have weird bowel movements that the crooks will tell you are gallstones. They can end you in the icu. We do live in a sea of unpleasant chemicals -- natural and human-made -- and the best you can do by your liver is to eat a healthy diet and stay physically (especially aerobically) fit. Get with an ethical holistic practitioner for some quality guidance.