Assuming the filter consists of a set of smaller metal mesh segments, a pot of hot water and baking soda could help. Here's how:

  1. Bring a large pot of water to boil on the stove and s-l-o-w-l-y stir in 1/2 cup of baking soda. (It’s going to foam a lot, so do this slowly!) 
  2. Add the filters and simmer 5 minutes or so. 
  3. Using tongs either pull the filters out or turn them around for another few minutes. 
  4. Run them under hot water (remember the tongs or gloves) 
  5. Let the filters air dry.