Hey Mr. Green, Are the colors in newsprint, junk mail, and advertisements--especially the glossy ones--made from heavy metals like lead and mercury, or are they vegetable dyes and safe to mulch into soil? --Francis in Mt. Shasta, California

Both black-and-white and colored newsprint are safe to use for mulch or compost. One study of newsprint's use as animal bedding found that it contained fewer heavy metals than plain old straw. But glossy magazines and colored supplements and inserts, which are often produced with heavy-metal-based dyes, should not be used in your garden. (Although Sierra's printer uses soy-based inks, magazine pages do not break down effectively in compost.) Now you've heard it here from Mr. Green: Do not compost this magazine, nor mulch your veggies with its pages, even if they sound outrageous; recycle it with loving care, or archive it for curious heirs.

Hey Mr. Green, What can I do with a small amount of used paint thinner? --Gerald in San Francisco

This is the kind of question "reduce, reuse, recycle" was invented for. Just pour the liquid in a can or jar and let the gunk settle at the bottom. When the liquid is clear, voila, you have reusable paint thinner you can pour off into another receptacle. Scrape the glop out, wrap it in plastic, and toss it in the trash. Then recycle or reuse the container.

Hey Mr. Green, I've contacted my power company and switched to 100 percent renewables. Is it still important to keep up with other energy-saving practices in my home? --Kelly in Sussex, Wisconsin

Darn right you should keep saving energy, for three very simple reasons: First of all, even if an energy source is renewable, that doesn't mean it has zero environmental impact. Windmills and solar panels require all sorts of potentially polluting industrial processes (and energy) to manufacture. Some windmills can also mangle birds and bats, hydroelectric dams drown big tracts of land, and growing crops to use as biomass can have serious drawbacks in the heavy demands it makes on the soil. So it makes sense to use these more benign sources as efficiently as you can.

Second, signing up for renewable energy doesn't necessarily mean that wind-powered current is actually buzzing from some turbine in the boondocks straight to your digital toys. Even though you've agreed to pay the utility company the extra money it needs to buy renewables, which cost more than conventional power, those more virtuous electrons might be going someplace else on the grid.

Finally, since it will be a long time before we have a surplus of kinder current, we should spare as much as we can for other concerned enviros. Oh sure, some economic wizards will probably claim it's good to squander renewable power because it'll increase demand, unleashing free-market forces that will spur power companies to invest more in renewables, blah, blah, blah. But since it was exactly such enthusiasm for squandering that got us into our energy mess in the first place, you may safely ignore such arguments.

CONTACT US Read more Mr. Green and submit your own questions at sierraclub.org/mrgreen, or mail them care of Sierra at 85 Second St., 2nd Floor, San Francisco, CA 94105.

Illustration by Melinda Beck; used with permission.