Article: White shirt collars tend to pick up built-up dirt, oils, and haircare products from the back of your neck, leading to grungy, yellowish discoloration. The next time you plan to put on a white shirt, jump in the shower first and give the back of your neck a good scrub with soap or body wash. If you don't have time for a shower, wash the back of your neck with a soapy washcloth or a cleansing wipe before putting on your shirt. If you tend to use hair products (such as gel or wax) or skincare products (like lotions or moisturizers), wipe the back of your neck before putting your shirt on. These products can easily pick up dirt and grime, and some may contain staining ingredients. Let any hair product dry before putting on your shirt, especially if your hair is long enough to touch your collar. The major culprit behind those aggravating yellow underarm stains is not your sweat, but the aluminum used in many deodorants and antiperspirants. A chemical reaction between sweat and aluminum creates the yellow discoloration. To prevent this problem, switch to a natural, aluminum-free deodorant that focuses on combating bacterial odors rather than blocking your pores. Look for deodorants that say "aluminum free" on the label, or make your own deodorant using household ingredients and essential oils. Some antiperspirants are formulated to both reduce sweating and prevent yellow stains. Look for deodorants that say something like "anti-yellow staining" or "fights stains on shirts" on the label. To fight wetness without shirt-staining aluminum, combine an aluminum-free deodorant with a sprinkling of absorbent Gold Bond or a little baby powder. Undershirts provide a barrier of protection between your shirt and your body. They may be particularly useful for preventing underarm stains. If you perspire a lot, look for undershirts with built-in sweat guards. Having a lot of armpit hair promotes excess sweating, especially when the weather is hot. Protect your shirts from sweat stains and reduce your need for staining antiperspirants by removing some or all of your underarm hair. Catching and treating stains early is key to preventing them from taking hold. As soon as you notice discoloration starting to develop on your shirt's collar or underarms, use a commercial pre-laundry stain treatment on the area. Wash or dry clean your shirt as soon as possible. Enzyme-based cleaners are especially good for tackling sweat stains.

What is a summary?
Wash your neck thoroughly before putting on a white shirt. Wipe excess hair and skin products off your neck. Switch to aluminum-free deodorant to prevent pit stains. Wear an undershirt to protect your shirt from sweat. Trim or shave your underarm hair to reduce sweating. Wash white shirts immediately after wearing them.