Our city has a ban on pesticides and other nasty weed killers. The problem is… we have an interlock driveway. Grass and weeds are constantly poking through the cracks in the brick (plants are resilient, aren't they?). So what is the hubby doing? He's spraying the driveway with vinegar. It does a great job (especially combined with the sun). The best part is that it is way less expensive than the fancy outlawed weed killers.
I'm a big vinegar fan. I use it to clean (vinegar and water is the BEST at cleaning windows, and it is a superb rinse agent for the dishwasher), to bake, and clean clogged drains.
Sharon Harvey Rosenberg has an entire mini chapter in The Frugal Duchess talking about kinder, gentler, and less expensive alternatives to household cleaners and laundry room helpers. The big three being vinegar, bleach (NOT together), and baking soda (who doesn't have a box of that in the fridge?), supplies our great-grandmothers used to clean with. Yep, what is old is new again.
Oh, and she has a section on the wonders of WD-40 too. I once interviewed people for a Gallup poll sponsored by WD-40, gathering tips on how they use that stuff. Did you know that some folks (mostly manly men puttering around the garage) use it to help with their arthritis? They rub it on their joints. Now, I don't know if I would do THAT but there are some other great uses.