How can I remove AutoNumeric formatting before submitting form?

Inside data callback you must call getString method like below:

        $("#form").autosave({
        callbacks: {
            data: function (options, $inputs, formData) {

                return $("#form").autoNumeric("getString");
            },
            trigger: {
                method: "interval",
                options: {
                    interval: 300000
                }
            },
            save: {
                method: "ajax",
                options: {
                    type: "POST",
                    url: '/Action',
                    success: function (data) {

                    }
                }
            }
        }
    });

I wrote a better, somewhat more general hack for this in jQuery

$('form').submit(function(){
    var form = $(this);
    $('input').each(function(i){
        var self = $(this);
        try{
            var v = self.autoNumeric('get');
            self.autoNumeric('destroy');
            self.val(v);
        }catch(err){
            console.log("Not an autonumeric field: " + self.attr("name"));
        }
    });
    return true;
});

This code cleans form w/ error handling on not autoNumeric values.

With newer versions you can use the option:

unformatOnSubmit: true