Step one:Rinse under a cold tap until the water runs clear.  Don't be tempted to use warm water - cold is much better for eliminating blood.  Soaking isn't necessary and can harm your underwear.Step two:Wash on a cold wash with your regular load.  Please do not use fabric conditioner or bleach (don't worry if you accidentally use fabric conditioner, they won't be ruined after one wash, just avoid in the future).Step three:Hang them on the line dry but if that is not possible dry them on an airer.  Please do not tumble dry (don't worry if you accidentally use tumble dry them, they won't be ruined after one wash, just avoid in the future).Step four:Step away from the iron!  Just incase you get tempted to iron your knickers please resist the urge as direct heat can damage the waterproof layer. Wash, wear, repeat!