Help with script to remove user from groups

This is a two-part question.

One of our user admin duties is to remove a user's group memberships when they leave the firm.  I found a script which worked the first few times I tested it but then stopped working for some reason (no error, it just didn't remove the groups).  I don't know Powershell well enough to figure out why.  I'm hoping that if I can better understand what each line of code does I can figure out where it's going wrong.  Below is the code which I have been running as a script file.  I'm using Powershell v2, I do remember to import the AD module and set the execution policy to remote signed, and I do have rights to perform this action:

Function RemoveMemberships
{
$user = Get-ADUser -Identity MKG -properties memberof
$userGroups = $user.memberof
$userGroups | %{get-adgroup $_ | Remove-ADGroupMember -confirm:$false -member MKG}
}

In trying to troubleshoot this I changed the confirm to true and it seems the problem is with getting the group memberships - it never prompted me to confirm removal - but I don't know what's wrong or how to fix it.  And frankly, experimenting with this particular script is something I'm a bit hesitant to do! 

Secondly, is there a way to better control the results of this cmdlet:  Get-ADUser - Identity TTESTER -properties memberof | out-file h:\mygroups.txt?

What I'm trying to do here is get a simple list of a user's group memberships and save it to a text file.  The results I'm getting include more info than I need. Not a huge deal but if there's a way to truly limit the results just to group memberships, that would be great. Here's what I get: 

DistinguishedName : CN=Testera\, Terry T.,OU=Milwaukee,OU=QBUsers,DC=na,DC=qb,DC=llp
Enabled           : True
GivenName         : Terry
MemberOf          : {CN=ALL ASG 1998 FIDUCIARY INCOME TAX,OU=App Security Groups,OU=Firm Wide,DC=na,DC=qb,DC=llp, CN=AL
                    L ASG 1998 FEDERAL GIFT TAX,OU=App Security Groups,OU=Firm Wide,DC=na,DC=qb,DC=llp}
Name              : Testera, Terry T.
ObjectClass       : user
ObjectGUID        : a870af2b-62cf-46e6-942e-7a44a8554cd3
SamAccountName    : TTESTER
SID               : S-1-5-21-57989841-1935655697-725345543-63788
Surname           : Testera
UserPrincipalName : TTESTER@na.qb.llp