Clear all your CloudApp items. Paste this code in your browser's javascript console after signing in to http://my.cl.ly/ and simply call deleteAllItems(), it will take a while depending on the number of items you have.

gistfile1.js

////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Clear all your CloudApp items.
//
//  Paste this code in your browser's javascript console and simply call deleteAllItems(), it will take a while
//  depending on the number of items you have.
//  --fms
////////////////////////////////////////////////////////////////////////////////////////////////////////////////

function getToken () {
    return $('input[name=authenticity_token]').first().val();
}

function getCurrentURLs () {
    var urls = [];

    $('input[type=checkbox]').each(
        function (index, element) {
            urls.push("http://my.cl.ly/items/" + $(element).val());
            return;
        }
    );

    return urls;
};

function deleteURLs (urls) {
    urls.map(function (url) {
        $.ajax({
            url: url,
            type: 'DELETE',
            data: { authenticity_token: getToken() }
        });
    });
}


function deleteAllItems () {
    var interval = setInterval(
        function() {
            var urls = getCurrentURLs();

            console.log("Deleting " + urls.length + " items.");

            if (urls.length === 0) {
                clearInterval(interval);
                return;
            }

            deleteURLs(urls);

            try { $('div#pagination').find('a')[0].click(); } catch (e) {}
        }, 5000);
}