Is your bathroom or kitchen sink mounted really close to the rear of your counter? Both my sinks are, and cleaning the gunk out of the tight spots behind the sinks drove me crazy before I thought of this idea. Use a child's paintbrush!
Need to clean your bathroom and out of cleaner? Toothpaste makes a great substitute for low-abrasion cream cleanser and leaves your bathroom minty-fresh. Just be careful; the fumes will make your eyes water, and clear your sinuses like nothing else!
The best way to clean glass shower doors is to use a good squeegee, right after you turn the water off. I have found the Cleret brand of shower squeegee's works best. I can quickly run it over the doors and all the tile surfaces in the bath.
We just brought a product called Spray Nine. It is for cleaning marina items (environmentally friendly) and does a great job. Well, it did one heck of job cleaning the inside of dryer without having to worry about the enamel being ruined or anything else.
This is a tip on cleaning fiberglass tubs. I found that pouring alcohol (plain alcohol or Japanese Saki works well) straight on stained areas of your fiberglass tub will make cleaning easier. The dirt and soap scums drips right off!
We have used Easy Off Fume Free over cleaner (for cold ovens, no heat required) to clean years of soap scum and hard water build up off showers and tubs, both fiberglass and tile.