For the last few years I’ve been cleaning my cylinder with bamboo. I use a large diameter piece of bamboo and split it into a piece just under the cylinder diameter. A little trimming on what was the inside cut, and depending on the thickness, maybe a trimming on the outside will leave you a flat, flexible and tough tool. It’s a simple matter to contour one end to fit the back of the cylinder. Place a patch on the end and clean away.