I Reckon that the key to any sort of deal especially if you want a freebee
is to approach it like you don't really need it but maybe offer an incentive
at the same time for example......
"What do you do with a all the used bus shelter polycarb you replace?"
example answer" we send it to landfill which is expensive"..
You might say " we will take it off your hands and save you tipping costs
and offer you a free advertising spot on our Robot Arena
Typical answers might be........OFF
or Yes please.