Black gunk accumulating

Black gunk which resembles mold but bleach will not remove is accumulating on the gray rubbet gasket attached between the washer housing and drum. Tried acetone, OOPS, bleach and scraping. It’s still there

Here are your parts
Replacement parts for MAYTAG MAH6500AWW | AppliancePartsPros.com

Here is a service manual
http://www.servicematters.com/maytag_library/docs/16010061.pdf

Here is a tech bulletin
http://www.servicematters.com/maytag_library/docs/TDL-0051A-B.pdf

See the following discussion about mold etc. is for a Whirlpool but much of it will apply to your unit.
http://forum.appliancepartspros.com/washer-repair/1807-whirlpool-washer-smells-moldy-whenever-idle.html

Just more info
http://www.applianceaid.com/neptune.html

Just Google “neptune mold” and you will see how common this problem is. Many people just leave the door partially open when not using the unit.
Also it is very important to use the recommended soap.