salt away

Also, salt down. Keep in reserve, store, save, as in He salted away most of his earnings in a bank account. This idiom alludes to using salt as a food preservative. [Mid-1800s]

Definition: save, store up
Antonyms: spend, throw away, waste

The verb has one meaning:

Meaning #1: keep or lay aside for future use
  Synonyms: store, hive away, lay in, put in, stack away, stash away