My father was a bit worried about the dye from the bath crayons my little brother uses leaving some deposits in the drain.
この場合、次のような言い方ができますよ。
ーMy father was a bit worried about the dye from the bath crayons my little brother uses leaving some deposits in the drain.
「父は弟のお風呂場で使えるクレヨンの色素が排水溝に沈着物を残さないか少し心配していた」
dye「色素」
to leave some deposit「沈着物を残す」
ご参考まで!