Create a backup of paths in a mat file -
path_list = path;
save('paths.mat','path_list');
Do your thing of removing 30 saved paths by going to Set Path
option on the File menu
and do whatever testing you were looking to do.
Once done with the testing, now you wish to add back the deleted paths. So restore the paths from the backed up mat file -
load('paths.mat')
path(path_list)