The lease specifically states that this is a non-smoking house and that "tenant understands that damage caused by smoking any substance will be their responsibility."

The gold has an underlying asset value and physical substance, where as bitcoin is like treasury bills, no true value unless others accepts it, as you can keep printing, loses the value.

Also, entheogenic substances are not "medicine." 

Because of the constant moisture and heat associated with showers, shower windows are always a hot spot for potential mold like substance. 

They had a raccoon in their chimney and the guy offered to get up on the 30 foot roof and take care of it if I'd buy the removal substance.

I wish I could add more of substance. 

To me, I think you'd be better off having a strong lease that prohibits the smoking of ANY substance (e.g. cigarettes, marijuana, crack, peace pipes, whatever) in the property and/or the growing of marijuana if you're concerned about that too (since that can also cause damage to a property).

If you want to treat a commission as a rebate, that's your prerogative and I'll wish you well.This is disappointing, since we both usually agree that substance overrides form. 

Also, the questions rises as to economic substance over legal form.

Use of illegal substances at the premises is also a violation of the lease (list the relevant sections of your lease...if you don't have this in your lease, add it for future tenants)."  ...when the tenant realizes that if they do take you to court, they'll have to explain to a judge why they were smoking marijuana in your property, they'll probably realize it's a bad idea to take you to court.Hopefully this helps ease your mind: what you're experiencing is very common--bad tenants who lose their deposit constantly threaten to sue landlords (and believe me: after about the 5th time it happens, you'll begin to ignore these types of empty threats).