In Lear’s final words of Act 1, Scene 4, he breaks off his speech to Goneril in order to address his own eyes, and then turns back to his daughter again:
Old fond eyes,
Beweep this cause again, I'll pluck ye out,
And cast you, with the waters that you lose,
To temper clay. Yea, it is come to this?
Let it be so: yet have I left a daughter,
Who, I am sure, is kind and comfortable:
When she shall hear this of thee, with her nails
She'll flay thy wolvish visage. Thou shalt find
That I'll resume the shape which thou dost think
I have cast off for ever: thou shalt,
I warrant thee.
The language here suggests a fairly covert metaphor, BEST interpreted as an allusion to the trade of a(n):