The phrase 'make them unusable' is correct and usable in written English.
You can use it when discussing how to render something or someone useless or incapable of functioning. For example, "The software update had bugs that made the printers unusable."
Slides would be so caked in mud as to make them unusable; roundabouts wouldn't go round; grass would go uncut.
Often, infection or other conditions make them unusable, and the scarcity has led surgeons to turn to live donors.
Decommissioning normally involves removing crucial components of the weapons to make them unusable rather than their complete destruction.
The child refugees also told of 4am police raids which, according to them, always involved tear gas or pepper spray, with most saying their sleeping bags were sprayed to make them unusable.
One estimate by Pentagon officials determined that Mr. Assad has 1,400 tons of sarin, VX and mustard agents, and that it would take at least 200 to 300 days to take control of the weapons and, short of destruction, to make them unusable.
But others have voiced a range of fears, including that not enough usable lines exist, that the owners of such lines will impose unreasonable conditions on research, and that the existing lines' possible contamination with animal viruses would make them unusable for clinical research.
This makes them unusable to touts.
Prior algorithms have lacked one or more of these properties, making them unusable for dense meshes.
They ended an old practice of moving and retraining regiments that made them unusable for at least six of every 24 months.
A further tweak to the gun law in 2008 means that inherited guns have to be fitted with a state-of-the-art blocking mechanism, making them unusable.
The underlying purpose of sustainable development is to help developing nations manage their resources, such as rain forests, without depleting these resources and making them unusable for future generations.
