Ive bought some random bags with minifigures inside.

Its obvious I need to open it to check the content?

\Whats the best way to do this to maintain maximum value?

Depends on your selling platform, but if selling on Ebay you can open polybag and put unbuilt contents in a clear plastic resealable bag 

If you are talking about CMF there are several smoosh guides for each series online. It's easy to determine what's inside each package by feel after a little practice. All it takes is a little time and patience. 

13 hours ago, terrymc4677 said:

All it takes is a little time and patience. 

And a 16-pocket apron.

Seriously though, it's pretty easy to smoosh to figure out the figure inside. IMO, it's better to sell them sealed than to open it and bag them up.

21 minutes ago, oneknightr said:

And a 16-pocket apron.

Seriously though, it's pretty easy to smoosh to figure out the figure inside. IMO, it's better to sell them sealed than to open it and bag them up.

I agree. I would just feel the bags out and determine which mini-figure it is. It took me lots of practice to master it, but like terrymc4677, it will take time and patience.

6 hours ago, oneknightr said:

And a 16-pocket apron.

Seriously though, it's pretty easy to smoosh to figure out the figure inside. IMO, it's better to sell them sealed than to open it and bag them up.

I thought it was a magic sorting basket? I was going to actually mention that but I didn't want to confuse the OP...lol.

Im going for the puncher. Its faster to check and minimal damage. And because my stock of "unknown content" is limited, its no big deal.