I presume you mean things like text boxes , check boxes etc? If so, for each item in your block style form, go to "other" in the properties and you will find an option for "Retain Value" - you probably have this as "true" at the moment. Having said that, I have had instances where it just won't get rid of old data, to over come this I set the values of each item to default values(could be blank) in the initialize_cb() section.