Washing is a very personal activity; my recommendations are based on my experience and best practice should you choose to wash differently you do so at your own risk.
Once used rinse in cold water, squeeze out gently (do not wring) and pop a wet bag or bucket unsnapped. If a bit dry at this point application of some plain soap and a little rubbing can work wonders to prevent staining. This said I don’t this and only once had issue. Busy ladies cant always rinse on the go, folding and waiting till home to rinse is fine from time to time as is leaving to soak in a lidded container until the evening. Try not to leave for more than 2/3 days before washing.
Pop them in with your regular wash at 30C, maximum spin 1200 and cool gentle tumble if you like. I recommend air drying if possible. Should staining occur place them damp in a sunny spot on either line or windowsill. Do not use fabric Softener/conditioner, this will coat the fibres and make them significantly less effective.
After a few washes your pads may feel a little thinner as the fibres settle, which is normal.
If well cared for the cores should remain effective for many, many washes.