In April, our Ask Umbra advice column turned 10 years old. To celebrate, Umbra Fisk sat down with an organic carrot cake and compiled the 10 most notable moments in Ask Umbra history. Spoiler alert! Her No. 1 highlight of the decade was you — her dear readers, whose questions “never cease to perplex, amaze, and amuse.”

Umbra is on vacation this week, so, as we count down to 2013, we rounded up the 10 best questions readers sent in this year. You can read her sage replies by clicking on the headlines.

Happy new year!

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Ball droppingly,
The Grist staff

10. Am I saving too many emails?

Dear Umbra,

I have some 11,000 emails sitting in my inbox and about the same number of sent emails. Would it be better to delete some? I’m thinking of them all sitting on a server somewhere — but perhaps their electronic cost is negligible? Related: What happens to people’s email accounts when they die?

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Catherine H.
Mamaroneck, N.Y.

9. Should I boycott my local gas station?

Dear Umbra,

Have you heard of “no gas Mondays”? Do you think the idea is a good way to make a statement about rising gas prices?

8. Why do bike tires suck?

Hello Umbra,

Through years of bicycle riding, I’ve never been able to pinpoint the exact reason why bicycle tires suck so badly. One fills a car tire with air maybe once or twice a year (really just checking the overall pressure), but a bike tire, it seems, has to be topped off over and over. Why are bike tires so lousy at their intended job of holding air under pressure?

John B.
Ann Arbor, Mich.

7. Is it OK to pour beer down the drain?

Dear Umbra,

I have two bottled beers in my refrigerator left over from a party at least three years ago. Incredible, I know, to anyone who loves beer, but I’m not a beer drinker. If this were cake, it would be a different story. Anyway, the question: Is it better to pour the beer down the sink and recycle the bottles — but then I’m adding an alcoholic pollutant to the waterways — or to put the full bottles in the trash?

Arlington, Va.

6. Got any good green jokes?

Dear Umbra,

Generally speaking, sustainability advocates seem to be a serious crowd. Have you got any jokes or one-liners that can bring some levity to our work? Especially ones related to recycling?

Robert D.
Jefferson City, Mo.

5. What’s that stuff in my bra?

Dear Umbra,

Lately I’ve begun to wonder about those stand-up-by-themselves, foam rubber bras that we women seem to have become addicted to because they provide some modesty (or much needed augmentation) for our spandex blend clothes. Is this stuff (said bras and our spandex-laden wardrobes) going to sit around un-degraded in landfills until after the Second Coming, or is it breaking down into substances that will turn as yet unborn children into 10-toed salamanders?

Should we be just saying no to the fashion industry?

Purrl Gurrl
Seattle, Wash.

4. Where do chemical-sucking plants go to die?

Dear Umbra,

So cacti can remove selenium from soil. I’ve read in the past about different plants being able to “sop up” various nasty chemicals. My question is this: Then what? Are they to be harvested and dumped somewhere, so contaminating another piece of land, or are they allowed to live out their lives, die, keel over, and re-contaminate the same piece of land?

David B.
Greenfield, N.H.

3. Is it ‘cheating’ to ride an electric bike?

Dear Umbra,

When I got my bike a year ago, I had high hopes that I would use it all the time in place of my car. But where I live, it’s just too hard to go anywhere with a load of groceries — I have a hard enough time lugging myself around. And it’s just not a bike-friendly town. I’ve found compatriots, but they all bike for fun or exercise. I want to use my car less, I want to use a bike more, so … I’m thinking of getting a motorized bicycle. Is that OK, even though it feels like cheating? Do you have any recommendations for one under $1,000?

Rockford, Ill.

2. Are we about to wreck space, too?

Dear Umbra,

I’ve been reading news about space mining and wondering whether destroying Mother Earth isn’t enough for us, so now we’re invading space! Or isn’t it that bad? Please enlighten me.

Ottawa, Canada

1. What will it take to change the world?

Dear Umbra,

Why all the focus on green liberalism? We all know that if everybody dimmed their lights for 20 minutes every day all the whales would sing and dance, but … everybody isn’t going to do that. In fact, many people have at the core of their identity a deep hatred of environmentalism. So do we bring them on board? Go over their head and change the law? And how?

Hugs and kisses,
Kevin H.
Phoenix, Ariz.