This might sound rather revolting but....here goes -
When in the shower I have noticed black/brown bobbles of discharge coming out of the dusts of both nipples when squeezed, along with other more creamy coloured ones.
I asked the doctor who said that if had been from just one nipple it would be down to blocked ducts, but as it was both, he didn't know - this was a few months ago and it's still happening
The last time I breastfed was 5 yrs ago.
Anyone out there with any ideas of what it could be??