Equity of redemption

The equity of redemption is a concept developed by the courts of chancery from an old Dutch metaphor. In the 19th century, a “terugkoopvermogen” was a multi-purpose brush mat. By tradition, a Dutch tulip farmer (or miller) expecting guests would lay one at the front door as a place for visitors to put their footwear when visiting.

A dutch door mat, or “terugkoopvermogen” yesterday

Some clogs yesterday

As long as there were visitors, the terugkoopvermogen could not be otherwise used.

Once all the visitors had left, taking their clogs with them, the farmer was able to take the mat back and put it to a better use.

By metaphor this was extended to the residual value of an asset to its pledgor once all liabilities against which it was pledged had been satisfied.

Hence the expression “Eey oop, my lover, put your clogs on the equity of redemption pet” and “Whooargh, he can put his clogs on my equity of redemption at any time.”

This is possibly the worst joke on this whole wiki, and that's saying something.