Santa Clara is having it annual cleanup drive through the first week of April. Just driving around yesterday I saw lots of bits that would make great additions to many a playa encampment. Poles & pipes of various types & sizes that would make great dome struts, bikes that with a bit of tuning and decoration would make suitable playa transport, netting like material to use for fencing to keep strays out of sensitive areas, etc.
Technically, it is illegal to poach stuff, but "everyone" does it, and I have never seen or heard of any citations or even "talking to's". Still, YMMV. The cleanup runs more or less north to south. Here's a link:
http://www.ci.santa-clara.ca.us/index-A ... ignMap.pdf