The cork edge is where damage shows first. If yours look pale, dry or slightly crumbly at the rim, that sealant has worn off. A cork sealer applied thinly with a cloth or small brush, once a year, is the single cheapest thing you can do to extend the life of the shoe — it keeps water out of the structure rather than making it look shiny.
Dry them somewhere airy, out of direct sun, and nowhere near a radiator. Heat is what cracks cork and hardens leather. Twenty-four hours in a hallway beats two hours by the boiler every time.
Can I put cork sandals in the washing machine if they're really bad?
No, and this is the one place I would be unbending about it. The drum soaks the cork, loosens the adhesive between the layers and usually leaves the footbed warped and the straps stiff, so a shoe that was merely grubby comes out genuinely finished. If they are past rescuing by hand, a cobbler who replaces footbeds and soles is a far better investment than a gamble on a 30-degree cycle.
How should I store them over winter so they're wearable in spring?
Clean and fully dry them first — storing a damp, dirty sandal is how you get mould along the strap seams. Keep them in a breathable cotton bag or an open shoebox somewhere with stable temperature, loosely stuffed with paper to hold the strap shape, and avoid sealed plastic boxes and lofts where damp collects. A quick brush and a fresh coat of cork sealer in March, and they will look like they have had a quiet winter rather than a hard one.
