So I want to wash three bed pillows before donating to a charity.

[flying_wahini]

9. I've washed foam and feather pillows in the bathtub -hot water and some oxide based soap.

Want to use as little soap as you feel you can, too much can muck it up and you can’t get it all out. . Soak them in the hottest water , plan of squeezing them out by hand several times. Soak and re soak a couple of times. You won’t believe how dirty they can get.
Rinse twice cooler water then get them wrung out enough to transfer to washer.
I then run a rinse only load with high spin. Transfer to dryer.
Tumble dry on low heat. Especially make sure that the feather pillows get REALLY dry.
A real bonus is the last step is finish off in bright sunshine for a couple of hours. Fluff and turn several times. Delicious pillows. Makes all the difference.