Bloodletting is a solution. Donate blood as frequently as they allow you. Plasma donation works even better (higher frequency) if you trust the machines and the process.
Sadly, it's not a complete solution as some harmful substances bio-accumulate in other tissues. A benefit may be had regardless as some substances leach back into the blood if the concentration gradient is sufficient.
Sadly, it's not a complete solution as some harmful substances bio-accumulate in other tissues. A benefit may be had regardless as some substances leach back into the blood if the concentration gradient is sufficient.