Firstly separate the filter from its stand by using a screw driver.
Next place the filter in a pan large enough so that it easily fits and is not hanging out from any side.
Now place this pan into the oven and heat it to as low as 250 degrees F. The more there is grease on the filter the more time it will require to stay in the oven to melt. Also, at this temperature not only the grease will melt but it will not let the grease catch fire.
To be on the safer side this requires extra care and therefore it is recommended to check the filter from time to time to see if the grease catches fire.
Once the grease melts out, take the pan out from the oven.
Next add some detergent in the dishwasher, put the filter into it and run it through the entire process for once.
Let the filter dry and then screw it back on its stand.
In a large pan add vinegar, dish washing detergent and hot water stir into a solution. Make sure that the amount of solution is enough and lets the filter get completely soaked in it.
Now remove the filter from its stand, use a screw driver for this. Put it in the pan and let it soak for 20 minutes or until the grease is removed.
Next with the help of a sponge or wire brush, clean the filter thoroughly from the place where there is a heavy buildup.
Once it is cleaned, leave it to dry and then put it back on its place.