California Universal Specialty Cap - Black - 5/8" Mesh Masonry Supplies You could use a vacuum

You could use a vacuum to clean them but a less time consuming method is to use the smoke shelf scraper to pull the ash down and shovel it into a container

3/4" Expanded Metal - Stainless Steel

Once in a while you run into a round flue liner in a masonry chimney

Anything the cap fits (95%)

California Universal Specialty Cap - Black - 5/8" Mesh Masonry Supplies You could use a vacuumCalifornia Universal Specialty Cap Black 5 8" Mesh Because the California Universal only fits about 95% of masonry chimneys in California, Chimney Products has some caps to fit the remaining 5%. the most popular (most used) is the 13"x13" which fits down to 8"x8" and everything in between (like 9", 10", 12" and 13" masonry rounds). They are constructed with the same quality materials as the California Universal with 5 8" mesh, and installs the same