yes, that is the best way, i try that before on a few filters, works great, very clean, totally no greasy thing anymore on the filter, after cleaning with soap and water, the filter will be less prompt for dust since there is no oil on it. then use a clean cloth to wipe it dry, tshirt should be able to do the task.
1. 1st gently rinse with flowing water to get rid of any solid particles that can scratch the lens.
2. Apply soap
3. Wash off the soap.
4. Flick off the water
5. daub off water droplets using either crumpled newspaper or lens tissue
6. Leave under fan or sun to dry.