Open almost any wallet that has been used for a while and you will probably find a few balances that look strange. A few cents of a token you do not remember receiving, 0.0000041 of something, or a USDC balance that refuses to go to exactly zero no matter how many times you hit swap. None of this means something is broken. It is a normal side effect of how tokens, swaps, and blockchains handle numbers, and it has a name: dust.
What counts as dust
Dust is a token balance small enough that it is worth very little, sometimes less than a cent, and sometimes less than the network fee it would cost to move it anywhere. It is not a special type of token. Any asset can end up as dust once the amount left in your wallet drops low enough that trading, sending, or even claiming it stops making practical sense.
Dust shows up for a few ordinary reasons.
Rounding. Tokens are tracked in whole units behind the scenes (what wallets call decimals, covered in our guide to token decimals), and a swap rarely converts an amount so neatly that nothing is left over. A route through one or more pools can leave a sliver behind after the math is done.
Leftover change from larger actions. Removing liquidity from a pool, claiming vested tokens in batches, or receiving a reward that pays out gradually can all leave small, awkward balances that never quite round up to an amount worth acting on.
Unsolicited transfers. Sometimes dust is not leftover at all. It was sent to you directly, often as part of a dusting attempt or an unwanted airdrop, which we cover in more detail in our articles on dusting attacks and unsolicited tokens and airdrop scams. If a balance appeared without you doing anything, do not interact with it, since some dust tokens are built specifically to bait you into approving a malicious contract.
Low liquidity. A token with a thin market can leave a small residual balance behind simply because there is not enough depth to fill a trade down to zero without the price moving too far.
Why a swap sometimes will not clear it
A decentralized exchange does not work like a simple calculator typing in a number and getting an exact result back. A swap quote is an estimate based on the current state of a liquidity pool, and the final output depends on exactly how much liquidity is available at the moment the trade executes, as explained in our piece on how a token swap works under the hood. When the amount you are trying to swap is tiny, a few things tend to go wrong.
Price impact can become large relative to the trade size, since even a small amount of slippage eats a bigger share of a tiny trade than a large one. Our articles on price impact versus slippage and swap fees and slippage go into why that happens. In the worst case, the expected output after fees and price impact rounds down to an amount so small the swap is not worth submitting, or a route simply cannot be found for it at all.
Gas cost versus the value of the dust
The more practical reason people leave dust alone is simple arithmetic. Every swap on Base requires a small network fee paid in ETH, covered in our guide to understanding gas fees on Base. Base's fees are low compared to Ethereum mainnet, which is exactly why clearing small balances is far more realistic here than it would be on a network where a single transaction can cost several dollars regardless of trade size. Even so, if a balance is worth a few cents, spending any fee at all to move it can mean paying more than the dust itself is worth.
This is a judgment call rather than a rule. A handful of small balances sitting untouched in a wallet costs nothing to leave alone. They do not expire, and they are not a security risk purely by existing. The only time dust deserves more attention is when it arrived without your involvement and the token itself turns out to have an approval request attached. Legitimate tokens sitting quietly in your wallet never ask for anything.
Deciding whether it is worth clearing
A few practical questions help here. Is the token something you actually hold on purpose, like a small stablecoin remainder, versus something you have never heard of that appeared unprompted. Does the value of the balance meaningfully exceed what a swap would cost in network fees. Is there enough liquidity for that token for a swap to even complete without an unreasonable amount of price impact.
If a balance passes those checks, swapping it into something you already use, most often the network's base asset or a major stablecoin, is a reasonable way to tidy up a wallet. If it does not, leaving it alone is perfectly fine. Unlike a cluttered desk, a wallet with a few dust balances in it is not costing you anything by sitting there.
The takeaway
Dust is not a glitch and it is not evidence that something is wrong with your wallet or a swap you made. It is the natural result of rounding, partial claims, low liquidity, and the occasional unwanted transfer. On a network with fees as low as Base's, clearing genuine dust is usually practical when it is worth doing. When it is not, the right move is often just to leave it where it is and keep an eye out for any balance that starts asking for permissions it has no business needing.