rebuilding brake booster - worth a try
 

I have a brake booster that I wanted to clean up but during process I got a little media inside. So I figured yeah take it apart,no problem got it apart in a little time etc. Now I got it all clean up but wanna make sure I put it back together right and was curious what type grease etc to use on the inside seal if any? Call me crazy I know why not buy new one but figured why I can learn something and 50/50 working right afterwards or just have to buy a new one. So any tips advice etc? Figured can't learn if you don't try!!!!