Upgrade your reclaimed boxes and bags by adding sturdy wire handles. Use 2-3 mm...

https://iris-wiki.win/index.php/How_Do_I_Make_Two_Wire_Handles_the_Same_Shape_Every_Time%3F

Upgrade your reclaimed boxes and bags by adding sturdy wire handles. Use 2-3 mm galvanized wire for strength and drill 3-3.5 mm holes for easy threading