Pump cleaning recommendations

I have the evenflo electric pump and I was wondering if anyone has any recommendations for non toxic cleaning products/ tips on how to clean it? I take it totally apart about once a day and clean it with mild soap and warm water, I even have a little tiny brush I use to clean the nooks and crannies... I have even tried letting the pieces soak and then cleaning. But the little piece that the milk actually goes through to get into the bottle STILL has nasty milk in it! How do I get that out!?