What I have found works is to scoop out as much as I can and then hit it with a dose of MPS.
I don't use a dishwasher but do use a filter cleaner in the summer months ... I have found using a bucket of clean water, inverting the filter (opening on top) and pulling the filter briskly from the bucket of water, soaking and repeating works great. I do this about 3 times - I soak the filter, pull it from the water quickly, push it back into the water, repeat about 4 more times, change water out, let it soak again in clean water for 1/2 hour and repeat ....
I have 2 sets of filters so it may be easier for me to do ....