Use a small section of a drinking straw for larger flies or section of plastic tube from a q-tip for smaller flies with a slit in the bottom for the thread to be pulled through as a inexpensive hackle gaurd. Leave the straw or tube in place when putting on the head cement as well to keep the cement off the hackles and just throw the straw out when it gets to much goo on it.
You can also use heat shrink tubing of diffrent sizes in the same way.