Drain one can of pineapple rings. This should be about 3/4 cup pineapple juice. Whisk together with brown sugar, dijon mustard, cloves and salt.
Transfer to a small pot and simmer gently until it thickens slightly and turns syrupy.
Use glaze as desired.
If you are wanting to add the pineapple rings with maraschino cherries, be sure to brush on some glaze first, then apply the pineapple rings and cherries with toothpicks, and then finish with more glaze in the last hour of cooking.
Notes
*Cloves is a very strong spice and is classically used in a pineapple ham glaze. If you don't like cloves, reduce this amount by half (so use 1/8 teaspoon) or omit completely.