I've always thought that stainless steel
was impervious to corrosion.

Recently, I was gifted with an engraved "hip flask".
On the bottom, stamped "Stainless Steel"
right next to the "Made in China " imprint.

The enclosed papers warn;
"DO NOT store any liquids in this container
for more than four days ! After that, drain, and rinse."

What aren't they telling me ?

I don't intend to work thru a flask of brandy every four days......

Stainless steel ??