It’s corrosion. If you clean it and it returns quickly, then the battery is leaking between the cast and the post and it must be repalced

When a lead acid battery like yours charges it produces a corrosive gas which is vented around the top of the battery filler caps. This gas has attacked your terminal, so first eliminate the corrosion using baking soda and water or coca cola to clean the top of your battery. Next apply either a battery terminal protector available at auto parts stores or you can use axel grease on the terminals to prevent more damage. When you have the battery cleaned up check to make sure there are no cracks on the top especially around the terminal.

Looks like off gassing from a vented battery. Check the alternator output and acid level in the battery.

ford battery, oem too and original to your car. dont play around with it, just replace it. try and find a deka or eastern penn brand battery, they have no vent caps like the ford battery does but instead little vent ports on the side. they will not leak like this one does.

It’s the original battery. Time to replace it.

Both. All battery terminal corrosion is from a leaking battery terminal or acid somehow making its way onto that connection, it is NOT caused by the electricity or anything like that, it is 100% of the time acid touching the metal and causing a reaction.

It is very hard, pretty much impossible to bond lead to plastic, most batteries are manufactured with an o ring embedded in the plastic to seal against the lead terminal. This often doesn’t help, acid wicks up and out.

Best thing to do is start off with disconnecting and cleaning the corrosion off of the terminals, install those felt anti corrosion disks, they soak up and neutralize the acid under the terminal where it’s coming from before it wicks up into the connection, protecting it, then spray it all down with battery terminal protectant, you’ll never have a corrosion problem after this.