Sorry to ask this mate, but I want to learn too. I have learned that dust as very tiny amount of Bitcoin, it could be 500 or 800 Satoshi or more. My question is, can custodian wallet not be able to accept such dust amount? The reason why I also ask this question is because centralized exchanges usually has a minimum deposit amount of Bitcoin but I have not observed such minimum deposit amount on custodial wallet. Last year, my friend lost his $10 worth of Bitcoin because he deposited on the exchange that required minimum deposit of $20.
@OP, check minimum deposit on Coinbase to know if it can receive the dust amount that you want to send, else you might lose the coin if it's below the exchange's minimum deposit.