I always try these two steps first. One get a larger pipe cleaner preferably fine metal wiring and ideally hook it up to a drill chuck.Stick it in the threaded hole and spin away. Follow that by running the complimentary tap through it. It also doesn't hurt to a shoot some wd40 in there while doing this.
" I told my son, you have to catch the football other wise this just looks like child abuse." - My brother