clever idea..
for canoe trips where the lunch switches back and forth from peanut butter or cheese on a MRE or heavy duty flat bread i like to use the plastic tubes.the screw top lets me use the tube over and over until used up without spilling anything.
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packing for the trip i heat the peanut butter jar in hot water until it pours and then it goes into the tubes without a mess.
the tubes still in the glass i have them standing in go's in the frig to set up,that way i can fold the top and put in that rod to make the seal without the butter making it's way out.a bit of tape as a "just in case" finishes things up.
i do the same with jam,dry things like sugar and dry milk also go into tubes.washed out after the trip they are ready to go again.