I recently rebuilt my absorption canister on my 1972 b. It was a nasty job but I was able to research several articles and get it done. The best way I found was removing everything from the canister first. Next I cleaned the canister along with the wire screen, washer and parts in the upper canister. I cut two filters from dish scrub pads. The first went in below the wire screen. I used activated charcoal pellets from a pet store and filled the canister and put the second filter on top of that. I had tossed the old charcoal, Next came the retainer, the filter pad and finally screw it all back in place. I hooked it up and the job was done.