RL is right, bleach yellows over time. It is better to use a degreaser on stains and dirty areas, then wash normally.
My favourite degreaser is the "Pink Solution"
website
I'm not a fan of using a lot of chemicals in my home. This product uses enzymes and is a non-toxic general cleaner. As far as I know, they only sell it on-line and at different home shows etc. I got some at a home show because my sister has been raving about it for years.
I tried it a few weeks ago on my 2-year-old fencing mask and now it looks new again. I also got some oil stains out of my knickers when I kneeled down to grab my water bottle when it rolled under my car and place my knee in an oil patch.
I use it as a spot remover, and as a general cleaner… essentially whenever I need to deal with grease. The oils from our bodies are the source of most of the grime along collars, and the front of our bibs. So this (or most degreasers) will do the trick.