Top Layer: if it was just stained by drink, pls use the tissues to absorb the liquid till the surface become dry.
If the cloth was stained by other stubborn stains, pls wipe the surface back and forth by one hand slightly with warm water and mild soap, and then line dry in the air.
Bottom waterproof layer: just wipe clean with damp cloth.
Clean it according to the washing instructions, keep in a cool dry place, if any smell after long time storage, hang it under sunlight will be OK.