Hats off to Higginson. Good work, that bricoleur. I imagine you flushed the caustic soda into your septic tank. Not!!! snicker, snicker. Way to go, dude.
I just rinse it down the drain with plenty of clean water to dilute it. It is essentially what you would buy as drain cleaner/unblocker anyway. If you don't want to do that, bottle it up and take it to your local tip, they should be able to handle it.
This is great. I have some locks like these that I have been meaning to restore but did not know how. Just one question, how do you dispose of the used caustic soda solution?
Great blow by blow description and photos, much appreciated James, where did you buy the Soude Caustique as I can never find the strong stuff needed for this type of work?