The unfortunate fact is that drug canine experts are seldom called to testify in court about the dogs' work. The only testimony usually taken regarding drug detection canines is usually from the handler who may not have the credentials to testify as an expert. Most people believe that currency becomes contaminated when a drug abuser snorts cocaine through a single rolled up bill and the bill is then mingled with other paper currency. This comingling supposedly contaminates all other bills. In actuality, most currency is tainted by scent contamination and not by actually coming in contact with drugs. Police dogs have a greatly enhanced ability to smell, but detecting and alerting are two different matters. Further, drug odor decreases in strength after a period of time and police dogs are usually trained to alert on a specific amount. If a properly trained dog does alert on currency, the amount of the illegal substance causing that alert has to be more than a gram. Police dogs represent a valuable tool in drug law enforcement, but their capabilities must not be overstated. 2 illustrations