Seriously, in an odd way this is taking the value of Depends and bringing it to the automotive world. I think when you say filter, you are talking about a drip pan of sorts, right? This idea does what I really think the best sorts of innovations do, they appropriate existing techniques and make them more polished. Everyone has seen the old cardboard under the car routine.

There might be technical problems pulling this off, but what about a version designed for sitting in the driveway or garage. It could be made out of a dark, recyclable and absorbent material. It could be weighted to keep it from blowing away, and would look better and last longer than an old box.

That being said, I propose a gadget or an under the engine snap on filter that would absorb leaks and be changeable in between oil changes. The filter should be large enough to cover the engine underneath and snap on fairly easy. No more leaks in your driveway or any cement surface. The device would have to be tough enough not to come off during the average operation of the vehicle. I feel that this type of product would be in great demand because late model cars are sold in the millions and many very probably have leaks. Please give me your thoughts.