"Modern" batteries (usually with the translucent white plastic case, but not always) aren't porous as the old black case (rubber?) batteries. As a kid, I lost a pair of jeans lugging a battery for my grandfather on my hip and dodging the dinosaurs that were common in the neighborhood. Jeans didn't rot away suddenly, but the next time theu jeans washed, it was clear where they were headed.
Here's a 12" x 8" battery mat for $12 on amazon:
https://www.amazon.com/Original-Battery-Mat-Protective-Black/dp/B098TRXXW1
But they don't ship to Hawaii.