In my opinion, you can lose the ash box. In my few seasons with an 88, get yourself a stout fireplace shovel (not a cheap pressed steel one), and a small 5-gallon galvanized tr(ash) can to scoop ash into. When you shake down the bed, shovel the ash into the can you've cocked the lid on, and gently dump ash in. Lay the ash and clinkers off the shovel instead of dumping from on high and it'll keep the ash down. Better, a cocked lid will help keep the ash down as well. Catching the business end of a (shop) vacuum hose between lid and rim as you shovel ash into the can will keep ash out of the room even more effectively. Do Not vacuum up hot cinders, just use the vac to pull in fly ash, and clean up any cool bits you may lose onto the hearth between ash door and bucket. When the bucket fills every few days do with it what you will (dispose of properly).