I'm certainly not the first to do this, but most are just picture tutorials. I thought it would be helpful to watch someone complete the process. Cheap circular polarization filters can be purchased online for as cheap as $5 each. The entire mod process takes about 10-15 minutes with the right tools. Easy and straight forward.

NOTE:
1. Take care not to damage the filter when unscrewing the retaining ring. It is easy to slip and scratch the class or coating.

2. There is a reason the Singh-Ray Vari-ND filter is over $300, but for around $10 a little color shift/drop in contrast/slight vignetting (all easily corrected in post) is worth the savings in my book.