What happens to all those election signs?

We've all seen the signs, during the election... but where do they all go once the election is over? Bangkok has quite a healthy industry of recycling for money. Garbage is picked thru most everywhere for ANYTHING of potential value. The recyclers or "salang" in Thai, are famous for cruising Bangkok streets with their modified 3 wheel pushcart-motorcycles. So as the polls close on 4pm on election day, it's gold rush time for the salang. They head out collecting the signs enmass. By nightfall, most signs have been scooped up. And monday morning, you'll be lucky to see any evidence of an election.

What do they do with the sings? Likely all kinds of uses from reuse as signs to roofing and home siding.