Another tool you can use is a rifle bore cleaning kit. I believe I used a .22 caliber brush, which has brass bristles. Worked very well.

Like "safe", I remove the plugs and the "indexing" bolt thingy and clean the spray bar in place.
Like "Werk-I"/Dave, I use a rifle cleaning kit. (Shotgun cleaning kit for the case main engine oil gallery.)

One more thing I would recommend, especially those who have turbo engines, is to clean the spray bar holes that direct oil to the valve train. An opened paper clip will work fine, but if you have a tapered pin that just fits into the hole, all the better. There are three holes per cylinder. This procedure will dislodge any coke bits that have wedged themselves into the spray bar holes.
Once this is done, apply the new spray bar plug to the front of the cam tower, then spray carb cleaner into oil feed hole of the cam tower quickly followed by compressed air into the oil feed. I say quickly because the carb cleaner dissipates very quickly. This will clear any debris out the spray bar and out of the rear of cam tower. Apply the new plug to the rear of cam tower and you're done.