Send your question to Umbra!

Q. Dear Umbra,

What is the greenest way to dispose of pet waste? Scoop and flush, or bag and throw in the trash?

Grist thanks its sponsors. Become one.

Jenifer M.

A. Dearest Jenifer,

dog signFlush or toss?The greenest way to dispose of pet waste is to dispose of your pet, I suppose. No pet, no waste! But barring that revolutionary scheme, a few other options present themselves.

You have not said what kind of pet you have, but judging by your reference to scooping, I am going to assume it is a cat. The time-tested advice for felines is to bag and throw away the soiled litter, including poo. If you are on a municipal sewer line, you may be able to flush the feces, but you should check with your town; if you have a septic tank, it’s not advised. By the way, when you choose kitty litter, don’t buy a brand that contains clay — you might want to consult our product tester for the best non-clay options.

Grist thanks its sponsors. Become one.

If you are scooping the waste of a dog or other animal, the same truth applies: bagging is best. It’s gross to think about all that pet waste rotting in landfills, but it’s a teeny bit less gross than imagining it seeping into our waterways or contaminating our gardens with its pathogens. (Some people compost pet waste, but it must be done very, very carefully — here are some tips.)

Of course, we hear occasionally about efforts to turn pet poop into power — I fur-vently hope “they” keep working on this idea, and I’m also very glad that is not my line of work.


Q. Dear Umbra,

I hear a lot about clean coal technology. Is it true that we can use coal in a “clean” way? I don’t believe it. Can you please explain this?


A. Dearest Anand,

You know the expression “go with your gut”? Methinks you should. You don’t believe coal can be used in a clean way, and you are right.

It is accurate, however, to say that coal can be used in a cleaner way than it traditionally has. Energy Secretary Stephen Chu and others point out that, since coal is abundant, relatively cheap, and unlikely to disappear from our energy mix any time soon, we should find cleaner ways of feeding our addiction. These include turning coal into a gas before burning it, and capturing and storing carbon dioxide emissions. Here’s a fun and colorful clean-coal overview from the BBC.

Will these “cleaner” methods prevent coal from harming our health and polluting our air and water? Will they stop coal companies from blowing the tops off of mountains? Will they keep miners from being trapped and killed underground? Not likely. There’s a reason my fellow Grist writer David Roberts calls coal the “enemy of the human race.” It is an outmoded, dangerous source of power. We should all lobby our utilities and our representatives to give us better, safer, healthier options.

I wrote a bit more about the clean-coal conundrum last year; you can find my answer here. I also recommend you swing on over to the Department of Energy to get a sense of their plans, and visit for a real, human understanding of where coal actually comes from.


Q. Hi Umbra,

I am a college student and I’m really involved in and passionate about making my university more sustainable. One of the issues that I am trying to address is our current disposal of mattresses. Every year, my university “disposes” of 1,200 mattresses by incinerating them for energy (people think this is awesome and sustainable — I wish I was kidding). So, I have been spending endless nights researching a safer alternative for this herd of mattresses. I can’t recycle them because it’s too damn expensive (about $20,000/yr). I can’t donate them because they are ripped and flat — who wants a holey pancake mattress? I can’t Freecycle them because bedbugs are a huge issue in my area and I don’t think I can find 1,200 people who want college student mattresses (think about what you did on your mattress back in the day…). So I am asking, I am BEGGING, you for help!

Mattress Maiden
Boston, Mass.

A. Dearest MM,

What I did on my mattress back in the day … let’s see, I slept on it. I read a lot of Aldo Leopold. I sorted my collection of fallen leaves by size and hue. What do you do on your mattress?

Never mind. The real question is, why is it so hard to dispose of mattresses in this country? I’m afraid, dear MM, you have outlined exactly the problem: Mattresses can rarely be donated, especially as bedbug concerns (real or imagined) increase. They take up too much space in landfills, so much in fact that some municipalities will no longer accept them. And though recycling programs are cropping up, they are few, far between, and can be fiscally frustrating.

Still, I think recycling is the best bet. Interestingly, Massachusetts is home to one of the nation’s few mattress recyclers, and another outfit is venturing into New England soon. It’s amazing what happens to your mattress: the wood is chipped for energy, the steel springs recycled, the cotton and foam used for insulation or other textile needs. I’m not sure which of the many fine Beantown schools you attend, but I see that Tufts and MIT both recycle mattresses. Those schools are dealing with a much smaller quantity than you mention, but you might contact them to find out how they’ve sprung over any obstacles. (You might also see if your school is retiring too many mattresses too soon.)

Another possible resource: Some schools rely on the help of the Institutional Recycling Network — you might contact them as well, if you haven’t already.

Above all else, it seems to me that the burning of these mattresses is a misguided plan. For one thing, mattresses are treated with chemicals to make them resistant to fire — so once they are coaxed to go up in smoke, they likely release all sorts of nasty fumes. That’s way more squirm-inducing than thinking about the damages that might have resulted from certain collegiate activities.

Stain removerly,




Reader support helps sustain our work. Donate today to keep our climate news free.