You have to wash that off with soap and water or it won't come off.
You need to scrub your hands with soap and water otherwise the ink won't come off.
1) You have to wash that off with soap and water or it won't come off.
「それ石鹸で洗わないと取れないわ。」
wash ~ off with soap and water で「石鹸で〜を洗い流す」
come off で「（汚れなどが）落ちる」
2) You need to scrub your hands with soap and water otherwise the ink won't come off.
「石鹸でこすって洗わないとインクが落ちないよ。」
scrub は「ゴシゴシこすって洗う」
ご参考になれば幸いです！
日本 
