impurity

Dear scholarsassalamu alykum wa rahmatullah. I have heard that if clothes get stick with urine or semen (madhi) then i have to wash it three times and also squeeze it hard after each time. And in case of sperm(mani) only once. Is it correct? Please explain in detail along with methods of washing clothes.

Dear scholars, As-Salamu `alaykum. Is it acceptable to wash clothes with impurities on them in the washing machine? Jazakum Allah khayran.

we have a 3 month old baby boy. since am a working woman, he is being fed a milk formula also. most of the time he is breast-fed only,but in my absence once or twice in a day he is fed the milk formula. i wanted to know whether his urine becomes najas because of this.if his urine falls on my dress,will just sprinkling water purify it and can i then pray with the same dress?or is it only after starting solid food that there is a need to change clothes before praying?waiting for your response...jazakallah...