You'd have to break it. Why?

 

They are sonic-welded, meaning the lens and the housing are fused/melted together. There are videos of people using a dremel to open them. Not an easy task at all.

 

I opened mine with the dremel method. Its time consuming becasue when you cut you have have to cut at the outer most edge so you can easily put them back together after you paint them. I dont know if after market lenses are easier.