Thanks for the replies. Apparently around here the tar is still the way to go. I purchased some in a spray can and sprayed it this afternoon. I am not too worried about bacteria b/c the average day temp is most likely too cold for bacteria and the hole was "open" for less than 24 hours. I honestly don't know if what I used was tar or not, there are no ingredients listed on the can - but - whatever it was came out black and sticky
Thanks for your replies!