This is a souvenir from before the coronavirus pandemic. I haven't used it, but it's a bit dirty. There's no visible deterioration. It's made of rubber, so I gently washed it with mild detergent to avoid scratches, but it's only so-so (^_^;). I think the dirt would come off if you used something like a "Geki-Ochi Kun" sponge. How about it for those who love Hawaiian things? It's also suitable for everyday use ♪