Baby formula has an odd smell to it to start; if you have a child that often tosses bottles around the house chances are you've encountered a bottle or two that's gone missing for a few days. When you crack it open the smell can be enough to knock you back a few steps. Trying to get that type of a smell out of a plastic bottle can be tough. Simply soaking them in hot soapy water isn't enough to get it clean and stink-free. I got the deluxe version bottle brush when I started baby sitting younger kids that still took bottles but realized that this can be used for a lot of other things. The bristles are strong yet flexible so you are able to clean the entire length and width of the inside of a bottle without have to force a sponge into it and using a fork to move it around to clean the gunk off the sides and bottom of it. I also use this for tumblers, sipper cups, tall thin drinking glasses and ceramic mugs. There is a small pull-out brush on the bottom of the brush that can be used to clean nipples; I also use this to clean the inside neck of wine bottles that have stains on them. The handle has a really nice textured grip to it so even if your hands are wet and covered with soap, you will be able to get a firm grip on it while you are using it. You can get them in a variety of colors and when it isn't in use it stands up perfectly so it will be clean and dry the next time you need it.