Window cleaner

This might not be officially "frugal," but it addresses a problem frugalites sometimes have: finding ways to bypass the questions and strange looks.

Use a little vinegar or ammonia in water to wash windows - that's commonly known - but if you want to fool your neighbors (spouse, mother-in-law, etc), put a drop of blue food coloring in it. They'll think you're using a commercial window cleaner.

Oven and grease cleanup

Put a half inch or so of ammonia in a shallow nonmetal container and leave it in a cold oven overnight. Fumes from ammonia is what does the job, so if you have grungy pots and pans, put them in there, too. The whole mess will clean up with soap and water and just a little elbow grease in the morning.

Stain pretreatment

Save those squirt dish soap bottles! One way to use them is to store solution to spot treat laundry stains. Fill the bottle with about a quarter cup of laundry detergent (NOT the kind with bleach in it) and a tablespoon or so of ammonia. Finish filling the bottle with water and use it like any commercial pretreatment: Squirt the solution directly on the stain, let it set for a minute, then launder.

Fool your neighbors

This might not be officially "frugal," but it addresses a problem frugalites sometimes have: finding ways to bypass the questions and strange looks.

Use a little vinegar or ammonia in water to wash windows - that's commonly known - but if you want to fool your neighbors (spouse, mother-in-law, etc), put a drop of blue food coloring in it. They'll think you're using a commercial window cleaner. If you can come up with an old spray bottle with a brand name label on it, so much the better, but maybe you can fake it somehow. All in fun, of course.