I doing my wash last night, and I've noticed that my collar is grayish in the back, I do sweat a lot during class and was my uniform everyweek.  Does anyone have tips on getting it little whiter?  Bleach is not the best option since I do have patches and lettering on my uniform and I'm allergice to Tide(get nasty rashes from it) so other ideas are greatfully accepted.

I hear Oxi Clean works well.

I use spray and wash on the collar, ends of sleeves and pant legs. Also on the arm pit area. I was also told to use less detergent (liquid) than what is called for and more water. Something about the detergent will actually make whites look gray if there is not plenty of water to rinse all of it out or something.  It seems to work well for us. Good luck!

I have a military/police/Master friend of mine who swears by "Bluet" for getting uniforms really white. I think it only works if the uniform is cotton though. Bleach will actually yellow polyester over time. (That comes from years of housewife/mom laundry knowledge)

every once in a while, i leave the laundary machine lid open so my uniform would soak there for a while.  that seems to get rid of noticeable sweat stains - even though the whole uniform stays greyish compared to new ones.