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Strange stuff below the boot carpet


11 Jan 2021
Left a 600 ml water bottle open in the boot today. Upon opening the boot the whole thing was empty. As we were going on a walk I only had time to lift up the divider thing and put that to dry.

When I got home I took the carpet liner to find out what look like years old encrusted cappuccino - realise now it's probably potassium carbonate from a battery leak which has crystalized into about 3-4 mm white / brown flaky stuff. Must have happened 4-5 years ago as not hasn't occured during my ownership. Brushed most of it out but the floor pan reinforcement (99750440300) that holds the compressor foam insert still doesn't look too clever. Now wondering how to clean it properly and safely.

Seems like there is some kind of drain plug on the floor as I couldn't find much water at all.
Pic of the affected part:


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Yes, on further investigation I think it could well be potassium carbonate. With this in mind, I will now proceed with a mask, googles and gloves on. The advice seems to be to clean it with baking powder.
I have to admit thats does look like battery acid corrosion ..

Carpets would have been destroyed though if it is battery acid .

There is a similar panel the other side .. if this has nothing on it then it kinda proves something leaked on that side .

I've seen water leaks here anyways and that doesn't do this .

A wire brush will do .. a respirator is needed though .. its more cosmetic than anything else as its pretty thick and this is merely surface corrosion .

I'm not aware of a drain plug in the floor pan .

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