Unable to delete custom fields

HI i have 2 custom fields that I can not get rid of. They are associated with a Post Type which is already deleted but when i try to "Permanently delete" the custom fields the page refreshes but nothing happens.

Its the first 2, Member ID and Level. Associated with find_a_designer post type which is nolonger.

Thanks in advanced

a:4:{s:18:"text_4df61de470bed";a:7:{s:11:"field_title";s:9:"Member ID";s:10:"field_type";s:4:"text";s:16:"field_sort_order";s:7:"default";s:20:"field_default_option";N;s:17:"field_description";s:78:"ASID Member ID. This should be a numeric code you received from National ASID.";s:11:"object_type";a:1:{i:0;s:15:"find_a_designer";}s:8:"field_id";s:18:"text_4df61de470bed";}s:23:"selectbox_4df6205e49519";a:8:{s:11:"field_title";s:5:"Level";s:10:"field_type";s:9:"selectbox";s:16:"field_sort_order";s:7:"default";s:13:"field_options";a:6:{i:1;s:8:"ALLIED E";i:2;s:8:"ALLIED P";i:3;s:8:"ALLIED I";i:4;s:6:"Allied";i:5;s:4:"PROF";i:6;s:8:"PROFESNL";}s:20:"field_default_option";N;s:17:"field_description";s:21:"Assigned by National.";s:11:"object_type";a:1:{i:0;s:15:"find_a_designer";}s:8:"field_id";s:23:"selectbox_4df6205e49519";}s:23:"selectbox_4cf582bd61fa4";a:9:{s:11:"field_title";s:8:"Duration";s:10:"field_type";s:9:"selectbox";s:16:"field_sort_order";s:7:"default";s:13:"field_options";a:5:{i:1;s:10:"----------";i:2;s:6:"1 Week";i:3;s:7:"2 Weeks";i:4;s:7:"3 Weeks";i:5;s:7:"4 Weeks";}s:20:"field_default_option";s:1:"1";s:17:"field_description";s:25:"The duration of this ad. ";s:11:"object_type";a:1:{i:0;s:11:"classifieds";}s:8:"required";N;s:8:"field_id";s:23:"selectbox_4cf582bd61fa4";}s:18:"text_4cfeb3eac6f1f";a:8:{s:11:"field_title";s:4:"Cost";s:10:"field_type";s:4:"text";s:16:"field_sort_order";s:7:"default";s:20:"field_default_option";N;s:17:"field_description";s:21:"The cost of the item.";s:11:"object_type";a:1:{i:0;s:11:"classifieds";}s:8:"required";N;s:8:"field_id";s:18:"text_4cfeb3eac6f1f";}}