you cant.
Generally,cocaine,heroin,meth etc. only stay in your system for 72 hours.
I don't think you can flush any drug from your system.
it takes about 28 days or a month to flush it completely out of the body.
Cocaine extensively metabolized primarily in the liver. Unlike marijuana which is a fat soluble substance Cocaine usually stays in your blood stream for about 8 days. You can purchase detox formula which will remove it in 2-3 days.
Drinking water does not remove cocaine from your system. Cocaine is metabolized by the liver and excreted through urine, typically within a few days. Drinking water may help flush out your system faster, but the most effective way to clear cocaine from your body is to allow enough time for it to be metabolized naturally.
Drinking plenty of water, staying hydrated, and getting plenty of rest can help flush cocaine out of your system. It is important to note that the best way to get rid of cocaine from your system is to stop using the drug altogether and seek professional help if needed.
How long does cocaine take to get out of the system
How long does cocaine stay in your system?
The heroin will be, but the metabolites they test for won't.
3 days
10 days
The general rule is that heroin, speed, and cocaine stay in your system for about 72 hours (3 days). If you can, though, I would wait at least 5 days, just to be on the safe side.