What's the cleanest way? I'm thinking warm it a bit, suck out the oil, puncture the filter? Catch drips with oil absorbent pads.

Punch a hole on the top center of the filter the night before. All the oil will drain to the pan and you can just take off the filter and put in a plastic bag. Been doing it this way for years and never get a drop in the bilge.

I never cared til I repainted my bilge this year.Thanks!

Why dont they mount the filters hanging down?

This works perfectly. Just taught that to a friend a couple weeks ago on his 500efi. He was astonished. 20-30 min is all it needed to drain out. Never spilled a drop. I always wondered why use the inverted filter as well, until I learned this method. Now it is a complete non-issue. Frankly, I'd probably spill more oil if the filter was hanging down and couldn't drain out the filter head in this manner.

And this is why it is inverted. Some vehicles are doing this now too. Using this method means less used oil on the ground/bilge/waterways.

IF you use a filter with an anti-drainback valve (which you should, Napa/Wix is my favorite for such), you will need to puncture the filter and the anti-drainback valve.

I took an old screwdriver that was just the right height to match the length of the filter without hitting the threads of the oil filter housing; and ground it down to a moderate point.
Pop that directly into the filter at Top Dead Center, and push it down all the way until it bottoms out. That will provide an air vent so it can drain sans suction slowing it down, and push the anti-drain back valve out of the way. The filter will drain in a few minutes.

My routine was if I was changing the oil, as soon as I back it in the garage from the previous outing, I extend the oil drain tubes out the back and into a 5-gallon can, and also puncture the oil filter as described. Then come perhaps the next evening, and close everything up, replace filter, and refill.

I used Wix filters with the anti-drain back and all I ever did was crack the filter and slowly work it up and rock it around a bit every so often, be patient (no more than a few minutes), and the majority of the oil would be out of the filter to where I could easily rotate it over the base and not spill any. I never liked the idea of puncturing a filter. Shouldn't take overnight to change oil.

It never "took" an overnight to do so. I just chose to leave it, and come back. It's so easy to do on a boat vs. a vehicle you have to crawl under, put on a lift, etc. I'm kind of AR about getting every last drop of old oil out on my vehicles; to the point where I'll pitch the vehicle so the last pit comes out the drain on the pan. On my racecar, I remove oil cooler fittings, and remove the oil from the cooler and lines. (FWIW, an outdrive fluid pump works great for filling an oil cooler on a racecar.)