You first spray something like resolve on the stained areas and let it set for about ten minutes then rub it in real good with your hands - between your knuckles- maybe spray it a second time depending on how stained it is then wash. Check if it is clean before you put it in a dryer. The dryer will set stains. If it has not removed the stains try pouring Clorox 2 on. Good luck
Get married. Women just have the knack. But here's a couple of tips. Spray the collars with a pre treatment. I use a Dollar Tree brand that contains oxygen cleaner. Or you can make your own by dissolving a cup of 20 Mule Team Borax in a pint of water and brush all collars and stains. wash as hot as possible adding the rest of your mixture plus 1/2 cup more detergent. Dry on a medium heat and make the last ten minutes no heat so you won't have much to iron.
Not to sound sexist, but the simple fact that for years women were the homemakers they knew every trick in the book. I can't recall the name of the product but it's awesome. I believe you can still buy it at your local market. It basically looks like a bar of soap, it's wrapped in a white & green cover & for the most part odorless. I'd get those lovely black rings around the collar from my ties. If you had to preflight or weren't hooked up to an APU & you're in Phoenix, well I at least had buckets pouring out of me. Just wet the collars & sleeves & bang, works like a charm. If somebody knows the name please forward it to everyone.
Try this...it works great. Supermarkets usually carry the spray cleaner called "Fantastic". Spray it liberally on dirty collar, wait a minute or so then scrub area well with wet stiff brush like a scrub brush or stiff nail brush to loosen the dirt (about 15 to 30 second scrub) then wash shirt in washing machine. This stuff also works great on clothing like t-shirts that have oil stains etc...(sloppy eating). Spray on and hand squish/scrub/rub to loosen grease then wash. I even clean counters, floors and appliances with this great stuff ("FANTASTIC"). I learned this from a Pro house cleaner.