I have been using my BG 4.0's for over a year for 2 kids. I started noticing a strong ammonia-like smell and started reading about what to do. I wasn't sure about stripping with the blue dawn soap because I wasn't having any leaking issues. I found a brochure from Cotton Babies that recommended using 1/4 cup bleach in the wash cycle once per month to prevent stains and odors. I tried it once and it definitely worked, I was paranoid about using bleach (I never use bleach for anything and only use Allen's Naturally for all of our laundry) so I did 2 extra rinse cycles. The odor definitely went away but now 2 months later I am noticing it again.
Does anyone else use bleach on a regular basis like Cotton Babies recommends? Anything else that may help the odor issue?