OK legal types, how about this:
1) Medium size shallow pan on the garage floor, holding water
2) Smaller size pan that is placed in the medium size pan that floats
3) Smaller sized pan collects oil from above
Does that not meet all the criteria?
Or better yet: Run a craigslist ad in help wanted soliciting dirty diposable diapers to be placed under your car nightly for 50 cents a day. Collect the 2 quarters from the rear bumper. Thanks.