Bulk Laundry Detergent Preferred for Work Clothes?

I have been on bing and some others, searching for solid reviews about a detergent which will eat grease stains but not my clothes.

What I have found is that many people waste much time providing the most obvious and generalized valueless answers to specific questions.

Here is an example of what I have read and there are millions of these people shooting out "how to do nothing" reviews.

http://www.doityourself.com/stry/greasestain#.U1nB41fm5UQ

Anyone know of a good cheap bulk laundry detergent that is powerful? I am starting to think I should dose my car / farm project clothes load with a 1/4 cup krud cutter in with the laundry (maybe after it fills with water to eliminate discoloration due to concentrated action on a single spot).

Second question. What would be a good stain blocker? Mineral oil sprayed on clothes? Skotchguard? I was thinking if I sprayed a mist of mineral oil on clothes and chucked them in the dryer, they would have the fibers infused with that and the grease and crud would be less likely to be permanent on the next go-round.

Not that I am looking for pristine clothes but having farm and hobby clothes that are decently clean is nice in my opinion.