Can the black twine be used for sewing machines?
The cords are not specifically made for sewing machines so it is probably best to say that they are not suitable. Some of our net-making customers have used the black cords for net-making by hand which uses sewing machines as part of the process but they are specialised machines.
Can I use the cord for Landry handles?
Yes, they are suited to lifting heavy loads and many of our customers use the cord for this purpose. 5mm is the most popular diameter enough for commercial dry cleaners as it is thick enough to grip. 3mm is strong enough but can be uncomfortable on your hands when lifting heavy bags
It is worth mentioning that polypropylene or polyethylene cord and twines are hard materials. For a softer material that will be kinder on your hands see Nylon cord category.