Question about storing/splitting powders

I need to split a bag of powders I have, and I was wondering how I should store it? I have 50g and am going to use some and give my friend the remaining 20g.

I'm not sure if powders are sterile in the first place... could I just put it in a ziplock bag, and since you end up filtering it anyway it'll be fine? Should I clean/sterilize the ziplock bag first? Should I add a packet of silica?

Thanks in advance for any help.

Really need to know!

I would PM PharmaHun. She/He??? seemed to know a ton of sh*t on this subject, but may have been ran off the site.

yeah thats fine. No need to sterilize it, jsut use a claen one and no need for the silica.