Most of the times such shitcois have a very low price that do not allow the person to sell to get rid of shitcoin. anyway just forget that shitcoin and worry about coins that are good. I remember the first day I started to trade, it was in yobit and I bought many shitcoins because at the time I did not know anything about trade. 2 years have passed and the shitcoins I bought on yobit are worth 1 satoshi and many were delist  of the exchanges