Wash jars, screw bands and lids in soapy water and boil them (except
lids) for 5 min.
Finely chop 4 cups of pineapple guavas.
Stir sugar into pineapple guavas.
Bring mixture to a full rolling boil (a boil that does not stop bubbling
when stirred) on high heat, stirring constantly.
Stir in pectin quickly. Return to a full rolling boil and boil for exactly
1 minute, stirring constantly. Remove from heat. Wait 2 minute until
the level of foam goes down. Skim off any foam with metal spoon.
Ladle quickly into prepared jars, filling to within 1/8 inch of
tops. Wipe jar rims and threads.
Cover with flat lids. Screw bands tightly. Invert jars for 5 minutes,
then turn upright.
After jars cool, check seals by pressing middle of lid with finger.
If lid springs back, lid is not sealed and refrigeration is necessary.