Here is the power steering fluid reservoir from a Volvo.
This is the vacuum tank off of a BMW intake manifold.
Here is one of the oil traps from a Saab Turbo.
Once the parts were removed from their respective cars, I cut the tops off of all the tanks. Some of the pieces had baffles inside that also needed to be removed. After all of this was done I was left with hollow plastic tanks with one open side, much like a cowbell. I made a mounting plate out of scrap metal brackets and added a 3/8" post so that it can be mounted in most percussion hardware.
Here are the completed wood blocks and the mounting bracket.