eat into

US /iːt ˈɪntuː/
UK /iːt ˈɪntuː/
"eat into" picture
1.

to use up a large part of something, especially money or time

:
Unexpected expenses are starting to eat into our savings.
The long commute eats into my free time every day.
2.

to damage or destroy something gradually, especially by chemical action

:
The acid began to eat into the metal.
Rust can eat into the structure of a bridge over time.