When you buy a new token on Solana, the network automatically creates a new Associated Token Account (ATA) for that token.
The cost of creating an ATA is roughly 0.002–0.003 SOL (around $0.40).
Astrum allows you to quickly clean up unused accounts.
How to Close Empty Token Accounts
Open the Pairs tab in Astrum.
Click the button "Close X empty active token accounts".
All unused ATAs will be closed, and the rent (SOL) will be returned to your wallet.