Toss it, liner and all, in the pail. Washed liners can be reused until they fall apart. No need to get diaper sopping wet. Not to get stains out, to sterilize. Borax and vinegar if you prefer.
Diaper rash is caused by a bacteria that converts urine to ammonia.
You must kill those bacteria before you put the diaper on the baby. Sunlight is good too, so you could dry them on a line. Set your load size one bigger than reality - for a small load set to medium. Soap and fabric softener both tend to make the diaper water resistant. Might have to go through the dryer twice.