For a mundler (I call it a muddler)or a pestle, check a kitchenwares store like Crate & Barrel. When I make my world-famous mojitos, I use that wooden tool that has a long handle and a flattened-off cylinder on the end. That thing that nobody knows what it is that comes with a pre-packaged set of wooden kitchen tools.
"He owned a little cabin on the Gander River where he kept his Hardy rods and his rubber hip-waders and his special mundle stick for mundling up a pot of fisherman's brewis—a mess of boiled cod and ship's biscuits and scruncheons of fat-back pork—on summer Sunday mornings." —David Macfarlane, The Danger Tree, 216
"Mundle, also mundel. Wooden utensil used for stirring various mixtures; shim, slice." —Dictionary of Newfoundland English, 338