A tire cut can be repaired by a technician using a process that includes:
Inspection: The technician examines the tire to assess the damage.
Cleaning: The affected area is cleaned to remove any debris or contaminants.
Plugging: A special plug is inserted into the tire to close the puncture.
Patching: A patch is applied from the inside of the tire to strengthen the repair.
Balancing: The tire is balanced with weights after mounting to ensure the vehicle runs smoothly and safely.
Here are some other things to keep in mind when repairing a tire:
Never use only a plug or patch: The injury must be completely filled with a suitable vulcanizing material or rubber stem, and a patch must be applied to the inner liner.
Never repair an improperly repaired tire: The tire must be scrapped.
Never substitute an inner tube: Do not use an inner tube to remedy an improper repair in a tubeless tire.
Avoid excessive spreading: Do not spread the tire or tire beads too much.
Avoid buffing the inner liner: Do not buff the tire inner liner too deeply, exposing the tire casing body (ply) cords.
If the tire has large punctures or irreversible damage, it's better to replace it.
You can also watch this video to learn how to permanently repair a tire slash: