Spray it with lead!
But what you are really asking is this ...
'How can I use light weed to rip off my friends ?'
Well spray it with green lead paint, arsenic, rat poison, plastic, sand and glass. This I'm sure would help your profit I mean weight go up, and would probably go smoked without any complaints as it does in my area.
If it's that light just keep it and enjoy it for yourself. Light weed is not good for the commercial grower, but it's great for someone who wants an ounce to last a month.
Dont tamper with it man, it's hard enough these days to get a good piece of green as it is.