It will also depend on what kind of test they give her. If it is blood, she is probably ok. THC moves quickly from the blood stream to the kidneys and liver. If its a tinkle test, the halflife of THC is about 20 days so that will make it iffy. If they take a hair sample, and she smoked enough, then it will show a trce amount until what was in the follicle grows and is cut.
There are some products that are mainly diruretics that claim to flush the system but really they just make you pee a lot....
"Pain heals, chicks dig scars..Glory lasts forever"......