I mean I started selling real estate it was a one page contract with  GASP  Carbon paper  I am sure there are many on this site that do not even know what Carbon paper is or was used for... :)

You can PM Kevin Carbon for more information. 

If it does not a carbon filter will remove all traces permanently and will need serviced roughly every 3 years.

Deficiencies may include, but are not limited to: burned out light bulbs, non-working smoke and carbon monoxide detectors, inoperable doors, windows, or locking mechanisms.F.

And some even require carbon monoxide detectors.

I have monitoring during renovation and when occupied by renters for Burgulary, Fire, Freeze, Carbon Monoxide, Water Leaks, and Gas Leak.  

Use in small amounts...can be harmful in sizing, backings or stuffing material.DO NOT use gasoline, lighter fluid or carbon tetrachloride.POG -Paint, oil and grease remover; available in hardware stores.

This won't work on epoxy groutYou also need rubber gloves goggles and a carbon filter mask.

I don't know if I am doing it right or not, but if I collect the rent in cash, then I write a reciept and keep the carbon copy.

There were 7 duplexes being sold around the corner from me in a nice neighborhood where all the duplexes were near carbon copies of each other.