Craft\AmFormsPlugin::onBeforeUninstall PHP Method

    public function onBeforeUninstall()
    {
        // Override Craft's default context and content
        craft()->content->fieldContext = AmFormsModel::FieldContext;
        craft()->content->contentTable = AmFormsModel::FieldContent;
        // Delete our own context fields
        $fields = craft()->fields->getAllFields('id', AmFormsModel::FieldContext);
        foreach ($fields as $field) {
            craft()->fields->deleteField($field);
        }
        // Delete content table
        craft()->db->createCommand()->dropTable('amforms_content');
    }