Hello. I have dealt with issue with 2 of my three daughters so I feel as though I am somewhat of an expert on this subject. When my oldest daughter got it in first grade I followed the manufactures directions for applying the shampoo. I also did all the washing, vacuuming, spraying, etc. She ended up getting reinfested so the second time I treated everyone in the house. My third daughter had not been born yet but everyone in the house had it except my husband. I treated everyone initially at the same time and then retreated one week later. I also was very thorough about picking nits out of the hair. We would spend hours doing this. My oldest daughter fell asleep one night while I was doing it
I washed evrything I could and what I couldn't I bagged for 2 weeks. I also did A LOT of reading up on this online and from some of the stuff I was reading I decided not to use the spray. Apparently it doesn't really work. Also vacuum, vacuum, and vacuum some more. Wash everything in HOT water and dry on HIGH heat and as I said if you can't, then bag it. Be vigilant with picking the nits out. We usually had at least 3 nit picking sessions every day for EACH person. So remember wash everyone's hair at the SAME time and RETREAT EVERYONE again in 7 days. Good luck. I feel your pain. It's a lot of work, time and money.