I use the Testors Liquid Cement with the metal needle applicator.  I found that magnetic winding wire fits in the needle tube perfectly and will prevent clogging completely without having to heat it up.  I just take a bit of the wire and wound one end for ease of grabbing, and then melted a bit of spare sprue on that end.  Then straightened the other end out and feed it down the tube.  I've been using the same bottle now for the past 20 years so it has gone a longggggggggg way and it is still half full!