To remove the Combustion blower...
1st make sure you have a replacement gasket on hand.
2nd turn off the power (unplug stove from wall)
3rd unplug 2 spade connectors going to combustion (exhaust) blower
4th remove the 6 little screws around the circumference of the blower plate
5th carefully pull blowet assembly out (taking care not to damage fins/blades on blower
6th take a small torx bit and remove blade/fins (if you dont remove, then)
7th take a small wire brush (size of a tooth brush) and carefully remove all build up on the blades (not bending) and scrape under the fins (if you didnt remove from shaft).
8th, some people spray down the blades with a Graphite spray, to reduce accumulation after reinstalled.
9th Add some oil to the bearing at the back and front of the motor. You can see where the bearings are. Some gets in and it does help.
Install new gasket, put screws back in, plug the spade connectors back in, plug unit in.
This should be done at least once yearly. Some do it more often. I normally do it twice. Once in the middle of season and then for the Big Spring Cleaning.
Here is my Spring Cleaning from the end of last season
https://www.hearth.com/econtent/index.php/forums/viewthread/75103/