Poke each amla well with a sharp needle all over. Dissolve alum and cholla in water and soak the amla in it for an hour. Wash in water and boil till the gooseberries turn soft. Drain and set aside. Dissolve saffron in 1 tblsp of hot water. Now prepare a syrup by thoroughly dissolving the sugar in 4 cups of hot water. Mix in the cardamom seeds and amlas and cook over a slow fire till the syrup turns quite thick. Remove from fire, cool, mix in the saffron, and cover each amla with foil. Pottle, and use when required.