The best way is not having to do it at all. But when it's your only option - here is my
method.

I use red catheter tubing (see picture) attached to a syringe - in this case I used a 10ml
and a medium tube (they come in all sizes, but you have to pick the most
appropriate for the bird). This should be a 2 person job....even really experienced
people should probably not attempt this on their own. Have one person hold the bird,
while the other inserts the tube. On a chick, the insertion is easy as their feeding
response inserts it for you. If you have an adult bird you are working on - looking at
the bird - insert the tube from the right side of the beak and down to the left side of the
neck (where the esophagus is located) and on down to the crop. Depending on the
situation you may need to use a tiny amount of KY or Petroleum jelly on the end of the
tube. Before inserting the tube hold it up to the bird to measure from the beak to the
crop, and mark a line on the tube where you should approximately stop inserting (so
you don't puncture crop wall - see picture).

The person holding should have the body with one hand and extend the head/neck
up with the other. For an adult bird - you may use 3 people. Once the tube is
inserted, the extractor must make sure that the tube does not touch the crop wall. You
can feel where the tube is and in babies you can see it in the crop. While holding the
syringe in one hand - manipulate the crop contents around the end of the tube. Push
up on the plunger slowly to pull contents out of crop. If you hit resistence make sure
you are not sucking the crop lining. If you are sure you are not against the crop you
may have a clogged tube. If contents are pulling out, you may slide barely slide the
tube up and down in the crop to keep the tube from clogging while you suction. If your
tube is clogged, you will have to pull out, unclog and re-insert. Once some of the more
watery contents are out, you should add a small amount of warmed (102-106 F)
Pedialyte, Lactated Ringers, or Saline Solution to the crop and gently massage the
contents to help break up the remaining food and make it soluble. Re-insert the tube
and begin suctioning. Depending on the severity of the compaction in the crop this
may take quite awhile and several attempts to get the crop emptied.

Once crop is empty, I give a dose of warm Pedialyte orally to help with dehydration,
and go from there.