Upgrade your reclaimed boxes and bags with sturdy 2-3 mm galvanized wire...

https://spencerssmartword.quillnesty.com/posts/what-is-a-good-test-load-for-a-new-wire-handled-box-before-i-trust-it

Upgrade your reclaimed boxes and bags with sturdy 2-3 mm galvanized wire handles for a reliable grip that lasts. Drill 3-3.5 mm holes to thread the wire through easily without tearing the material