If you see something like that:

$ git fsck --lost-found
dangling commit 9dbd85d427b32773aee016efc7912f9d1c39aac4
dangling commit 604948146be1bdc2181962543cca039c18cc06b4

You might want to get rid of those dangling commits, in order to accomplish it, do following:

git reflog expire --expire=now --all #Dangerous command, it will be very difficult to recover stuff later on, if you execute it
git gc --prune=now