Tying String Around Ear Keloid for Removal?

Tying a string will strangulate the blood supply to any structure and result in it falling off. This includes keloids. This question is both technical and prognostic.

Can you tie a string around the base? Is it narrow enough?
Will it recur (come back)?

Certainly there is little blood supply, and keloids are dense as well as tender. So this may be uncomfortable. It may also not produce a satisfactory result from an apeearance point of view. However, there would appear to be little risk.
In summary, this could work but it clearly is not the standard of care.

This "string strangulation" method may very well work.  However, it is important to understand that a keloid is an abnormal wound healing response with different histological characteristics than normal scar tissue.  Your method may solve the problem, but it is generally agreed that any form of keloid excision carries with it a 50% recurrence rate.  Don't be surprised if it returns within a few months.

You are suggesting unconventional treatment but it might work.  However, once it falls off, the recurrence rate would be high unless it is simulataneously treated with steroids or pressure.