Can Charcoal tablets get rid of THC?

No, scientifically charcoal will not "get rid of THC" which is actually very hard to do. Charcoal cannot flush or mask marijuana in a urine test.

Most schemes to pass a marijuana test will either dilute the urine or mask it with chemicals so the sample passes a quick stick test. This does not do much good if they send the sample to a lab for further processing.