It will be a pain if my (scarf) gets dirty, so I'm going to take it off
I don't want my (scarf) to get dirty so I'm going to take it off
「(マフラーが)それ、汚れたら困るから、はずすよ」= 1番は直訳なんです。2番のほうはもっとナチュラルだと思います。
「汚れたら、マフラー使えなくなっちゃうよ、洗わなきゃいけないから」=「If my scarf gets dirty I won't be able to use it because it will need washing」
「ご飯、食べ終わったら、またマフラーしようね」=「Once I finish eating, I'll put it(my scarf) back on」
You don't want to get food on your scarf, you better take it off.
If it gets stained, I'll have to wash it, which means you won't be able to wear it.
You can put it on again after supper.
この場合、次のような言い方ができますよ。
ーYou don't want to get food on your scarf, you better take it off.
「マフラーに食べ物がついたら困るから外そうね」
ーIf it gets stained, I'll have to wash it, which means you won't be able to wear it.
「汚れたら洗わなくちゃいけなくなって、着けられなくなっちゃうよ」
ーYou can put it on again after supper.
「夕飯の後また着けようね」
ご参考まで!