The footbed: the grey shadow of a whole summer
Start completely dry. Take the sandals outside or over a bin and knock them together to lose the loose grit, then go over the footbed with a stiff dry brush — an old nail brush or a suede brush is perfect. A surprising amount of the greyness is simply compacted dust, and it lifts before you have introduced a single drop of liquid.
Then make a small amount of warm water with a squeeze of mild soap, dip the brush, and shake off the excess until the bristles are damp rather than dripping. Work in small circles across the footbed, paying attention to the heel cup and the toe ridge where the discolouration is deepest. Wipe away the lifted dirt with a barely damp cloth, then blot hard with a dry towel. Repeat in a second light pass if needed rather than going in heavier the first time.
For smell rather than colour, let them dry completely, then tip a spoonful of bicarbonate of soda into each footbed, spread it with your fingers and leave overnight. Brush it out in the morning. It will not perform miracles on a sandal worn barefoot for five years, but it genuinely takes the edge off a single season.
Straps, cork edges and drying
Suede and nubuck straps want a suede eraser or a clean pencil rubber for scuffs, then a brush in one direction to lift the nap. Smooth leather straps take a wipe with a barely damp cloth and a thin layer of leather conditioner once dry. Synthetic straps are the easy ones: soapy cloth, rinse cloth, dry cloth.
