I am trying to flush out oxycodone and benzo overnight..what is the best way to rid my body of these drugs...how can i do that overnight..urine test?

Be careful: There is no guarantee that you can get these drugs out of your system overnight. Because of the half life, most urine and blood tests will show up positive. More concerning is that sudden withdrawal from these medications may cause severe side effects which may be far worse than having a positive urine. Seek help from your physician and be honest to keep safe. Good luck.

Physiology says no.: Drug tests usually look for a metabolite of a drug, not the drug itself per se. The time it takes for these drugs to come out of your body follows laws of physiology and pharmacology. There is not magical mixture which will flush them out faster- but people will try to sell you something anyways. Some can interfere with tests or temporarily hold metabolites- but not for those drugs.