Slice guavas 1/4 inch thick into a thick-bottomed saucepan and cover with water.
Simmer steadily for 50 mins until soft.
Allow to cool
Strain through a jelly bag.
Measure the liquid and return to washed pan.
Add an equivalent amount of sugar.
Add 1 Tb Sp lime juice for each 2 cups of liquid.
Stir until the sugar dissolves then boil rapidly, skimming from time to time, until setting point is reached.