The term "dust" in bitcoin refers to a very small amount of bitcoin that costs more to send considering the minimum transaction fee. It usually is around 500 satoshi although it can change and has changed with the price.

$6000 today is 0.1343BTC which is far from being "dust", not to mention 4 years ago it still was a considerable amount of bitcoin since in 2017 price of it were between $134 to $2680 and nothing in that range can be considered "dust".