Tea that is made from tea leaves that have already been used is not good.
When you use tea leaves more than once, the tea doesn't taste very good.
日本語で言うと簡潔に言えますが、英語で言うと少し長ったらしくなってしまいます。
1) Tea that is made from tea leaves that have already been used is not good.
「すでに使った茶葉で入れたお茶は美味しくない。」
2) When you use tea leaves more than once, the tea doesn't taste very good.
「茶葉を２回以上使うと、お茶はあまり美味しくなくなる。」
「出がらし」は tea leaves that have already been used や tea leaves that have been used more than once または簡単に used tea leaves とも言えるかと思います。
ご参考になれば幸いです！
日本 
