One of the best ways I've found to eliminate lingering cannabis orders is to use clean cannabis. The terpenes and oils from cannabis fade their aroma within a few hours.

Poorly grown cannabis will leave a dirty ashtray smell, like tobacco smoke does. Dispensary cannabis almost always leaves a dirty ashtray smell.

I'm working on teaching more folks how to grow cleanly. ;) You can find my book "Secrets to Growing Trichome Dense Cannabis" on Amazon.