Mystery white residue inside fuel hose clamp connections

I am going through and replacing fuel hoses on my 87 328 little by little. So far, both the tank-pump hose and the two connection pipe sleeves have had white residue between the hose and fittings. Here's a shot of the pipe coming down from the right tank:

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Here's what the inside of the corresponding hose looked like after being cut open -- other than this white stuff under the clamps, the interior of the hose where it held gas looked fine:

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Here's the hose that runs from the left tank to the fuel pump, more white stuff -- that hose spun freely on the tank nipple fitting before I loosened up the clamp:

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I would normally suspect aluminum corrosion, but in that last photo, the end of the hose we're looking at was on the tank nipple fitting, which is plated steel. So it's obviously not aluminum corrosion.

I tried wiping off the residue with wd-40, gas, mineral spirits, acetone, and alcohol. No dice. But if I let it dry and pick at it with a fingernail, it will slowly come off.

Here's what the one end of the tank connection pipe looks like after I picked at it and wiped it clean. Whatever that stuff is, it caused some light etching in the aluminum surface. Barely enough to feel with a fingernail, but there.

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Anybody seen this before? Any guesses what this residue is and any ideas to deal with it? I've been working on vehicle & marine fuel systems for decades and don't recall running into this stuff before. Since it's on the part of the fitting under the clamps and external to the clamps, but absent from the part of the hose that was bathed in fuel, I am half wondering if maybe it's the result of whatever lubricant the factory used to put the hoses on.

 

For sure ethanol can cause something like this -- I've seen it a lot in marine systems. It's usually due to stripping of oxidation off aluminum tanks/parts or deposits that occur when water and ethanol interact and do strange things. But that has always been inside the fuel systems, in areas wetted by fuel. This is the first time I've seen anything like it on the outside of a connection (and no signs on the inside). It's possible the old hoses absorbed fuel and wicked it past the barb under the hose and clamp. I hadn't thought of that, but ethanol does mess up old hoses so it could be the cause here. The areas outside the barb would have probably dried out and maybe made it even worse.

Thanks for all the input, it's good to get opinions. I am going to try morcal's suggestion and see if vinegar can get the white stuff off the pipes on the fuel tanks. I was not looking forward to laying under the car and scraping those off with my fingernails.