my son slept in the bed with me last night, I decided to use these cheap diapers I got from my baby…

my son slept in the bed with me last night, I decided to use these cheap diapers I got from my baby shower just to get them out of the way and he instantly leaked through it. so there was pee all over our sheets, and it went through our mattress cover so now there is pee all in the mattress. what's the best way to clean a mattress?