I've used powdered Tide detergent forever, and have been happy with how it cleans, but Tide alone hasn't been able to fix built up oils in pillowcases. I learned detailed steps for laundry stripping on Reddit.
The water is supposed to stay hot for hours, and many people strip laundry in a cooler, so I lugged our heavy 15 gallon cooler up the steps and put it into the bathtub so it could be easily filled and drained. Filling turned out to be a problem because the cooler wouldn't fit under the spigot, so I folded a flexible cutting board to shunt the water into the cooler.
I filled the cooler halfway with hot water (about 7 gallons) and added 1.5 cups of Tide with Bleach (which contains both lipase to cut oils and oxygen for stains and odors). I used a paint stick to stir the solution until the detergent was dissolved, then added two sets of sheets and submerged them. I sealed the cooler and let it soak for 8 hours. The water was quite warm still after 8 hours, so the cooler worked. I drained the cooler into the tub and used a 5 gallon bucket to get the drained sheets to the washing machine. I set the machine to hot water, heavy soil and an extra rinse, and I poured 1 cup of 4% ammonia solution on the sheets and put Tide powder in the dispenser. I cleaned the cooler with vinegar and then Simple Green to limit the scent of the detergent.
The pillowcases did come out whiter and cleaner. This is a fair bit of effort, so I wouldn't see doing this more than 1-2 times/year based on need.
