Delete unnamed custom fields in "Add Venue"

hi, I need to delete 5 entries ... how can I do? .. See image ... Thanks.

Sorry, currently that is not possible out of the box.
With good knowledge of CSS you could set these rows in a custom CSS to:

It is better to use jem settings>global params
Number of custom fields!

Oh yes, indeed. Out of the box!
Of cause that does only work if one uses only the consecutive first x custom fields.
If you change your mind and want to delete one of the custom fields in the middle at position y, you will have to change at least all open events for a reuse of the custom field y with the value of custom field x, then rename custom field y with the name of custom field x and finally reset the number of custom fields in jem settings>global params to x-1. Even more work might come up, if you want to preserve the sequence and y < x - 1.