Maintaining an attitude of proper homebrew sanitation is necessary for any home brewer. There are many forms of bacteria, including vinegar, and rogue yeasts which threaten the quality of our homebrews, and they must not be given the chance to breed in our brewery workshops. Often, I have met brewers that only slacked a little in their cleaning and sanitation and the results have been terrible. Each home brewer should have a homebrew cleaning kit that covers all the bases. Scrubbing and sanitizing carboys are important, but it is with the plastic tools of the trade that problems most often occur.
Plastic parts are prone to scratches - it is inside these scratches that bacteria hide and take shelter from cleaning methods. Both siphon hoses and the plastic lines going in and out of your beer kegs suffer form this problem. One should clean and sanitize the lines of one's keg every time it runs dry. Depending on how much you and your friends drink, this may seem like it is too often. If so, then clean and sanitize them at least once a week. This will prevent the "back up" effect of bacteria sneaking down the lines into your brew.
One common mistake made by beer brewers when bottling beer at home is bottling in a carpeted room. Spillage is always likely to occur when bottling beer, and carpets absorb and stay wet for quite a while. This is an ideal environment for bacteria and vinegar colonies to breed in, and threatens your homebrew sanitation. It is always better to bottle in a non-carpeted area, one that can be mopped afterwards with bleach (which should be part of your homebrew cleaning kit: mop, bucket, and bleach).
Another common mistake in homebrew sanitation is allowing your carboys to foam over through the airlock. Many brewers underestimate the vigor with which their yeast develops in their brews. In the first few days, the yeast "goes nuts" devouring all the sugars in the wort, producing CO2 so rapidly that many bubbles and much foam results. The foam can develop so quickly that it bubbles up into the airlock and even out of it. Sometimes the airlock becomes clogged and even blows off the top of the carboy. Needless to say, this threatens your homebrew sanitation protocols. The best way to avoid this is to leave lots of space (about one gallons worth of room) at the top of the carboy. Under certain circumstances, even this much room isn't enough! In the event of having your airlock blow off or get foamed over, it is best to throw that airlock out, for re-using it may lead to contamination of further batches. The reason for this is that no matter what tools you have in your homebrew cleaning kit, you will not be able to get in there and scrub off the residue left by the foam.
The following chemicals and tools are useful and should be in your homebrew cleaning kit: Iodophor (or Iodine solution), bleach, mop, bucket, carboy scrub brush, high pressure bottle cleaner nozzle, scrubby pads, beer line cleaners, and steel wool pads. The carboy brush, scrubby and steel wool pads are strictly for scrubbing off your brewing supplies - this is just the first step to cleaning them. The Iodophor, bleach, and beer line cleaners are for sanitizing. Sanitation can only happen once all foreign matter has been scrubbed off of the surface to be cleaned. Otherwise, harmful bacteria hide in the layer of grime.
The use of Iodine solution as a primary cleaning agent works fairly well, although it usually causes unsightly rust colored stains, and can harm the taste of your beer if not rinsed properly - more so with bleach. Bleach is highly effective, but somewhat dangerous to use and after a long contact time with the surface to be sanitized, and also requires a long time to rinse it out. Usually a triple rinse is needed to insure that further batches won't be tainted by a slight bleach taste. Bleach is to be used for sanitizing glass, and not stainless steel. Bleach causes a reaction with stainless steel that can ruin in. Still, I recommend having both these items in your homebrew cleaning kit. Iodophor for sanitizing pots lids and spoons, and carboys, and bleach for sanitizing bottles. The high-pressure bottle wash nozzle makes the 2nd and 3rd rinses of the bleach-cleaned bottles very easy. IMPORTANT - It is recommended to use safety goggles when dealing with these high power cleaning solutions, as to avoid damage to the eyes.
I recommend Iodophor as the best of beer line cleaners. The best way to use Iodophor is to create a solution with water (according to the ratio on the Iodophor bottle) in a one-gallon bucket of water. After taking apart your nozzle and hoses, let all the arts soak in the Iodophor solution for about ten minutes. This will kill the unwanted bacteria, and if your solution of Iodophor and water is in the right ratio, will require no rinsing. Another technique is to make one or two gallons of solution and run this through your beer lines for about few minutes as a slow stream, the close the spigot and leave it for another few minutes (ten minutes total). This will sanitize the insides of your beer lines, but the outsides will still have to be sanitized. There are many kinds of beer line cleaner on the market to experiment with. Try some other beer line cleaners out and see which one works best for your home brewing needs.
Cleaning and homebrew sanitation may be the most tedious and un-glamorous part of home brewing, but it is very important. It is nearly as important as drinking the brews! Each home brewer develops different techniques and has different tools in their homebrew cleaning kit, so make sure to network with others to find out more tricks and tips for maintaining proper homebrew sanitation.