Is there a way to deal with mold built up on the washer bellow tub?
I once moved into a place with this problem. The clothes absolutely stank after washing. The gasket/seal (not sure what to call it) was visibly stained with mold, but I could not be sure if the bad smell or the spores or what it was came from the gasket or from some other parts inside the machine. I guess the "outer tub" surrounding the "perforated rotating inner tub" (aka drum, aka basket) is likely to also be stained, when the gasket is.

I did everything I could without disassembling the machine, and nothing helped. 


Cleaned all accessible parts with detergents and clorine
Washed several times on 90 degrees, first with lots of detergent, and then with clorine  (I guess washing clorine at this temperature may produce toxic gasses, but this washer was in a tool shed so I took the chance)
Washed with some anti mold agent


Nothing helped. The mold in the gasket got less visible, but was still hard to not notice, but the smell never got better. As far as I remember I could not smell anything from the machine itself, and when I took out my clothes it smelled ok, but then I hung it to dry indoors, and within an hour the whole room stank. 

It might be possible to fix it by disassembling it, I would not know about that.