Aladdin thermos? I had at least a dozen, and any one of them that is younger than 30 years old has lost its vacuum seal. Sure they won't break but won't keep liquid hot for more than 3 hours without that vacuum seal.
"This antique brass glass with handcrafted engraved design was given to my grandmother on her wedding around 55 years back & now is used by my mother."
Aladdin thermos? I had at least a dozen, and any one of them that is younger than 30 years old has lost its vacuum seal. Sure they won't break but won't keep liquid hot for more than 3 hours without that vacuum seal.