Storybook Land roof corroded by urine

[snopes]

Comment: According to a book I just read, {Little Known Facts About Well
Known Places - Disneyland, on page 116} - "while experimenting with
methods to make the miniature church roof in the Storybook Land Canal Boat
Ride appear realistically old and weathered, a designer discovered that
urine has an extremely corrosive effect on metal. So..." While the mental
image of someone peeing on a tiny church at Disneyland is bizarrely
hilarious, is there any truth to this?

[musicgeek]

Not sure if it was Storybook Land, but I'd swear I saw the "roof purposely corroded by urine story" on the boards before.

ETA: Here we go.