Shell Programming and Scripting

I am working on a Korn shell script that will cd into multiple directories that are listed in a flat file and gzip the contents of each directory.
So far, this is what I have:

1) Find the 4 largest directories and place them into the file foo

du -sk /some/directory/* | sort -rn | head -4 > foo

Sample output: 390216 /first/Big/Directory
44441 /second/big/Foo Junk <---notice space after Foo
22873 /third/big/Dir
11817 /fourth/big/Dir_ectory

2) So that I can capture directories that may have a space in them, I am using the following:

cat foo |\
sed -n 's/^[0-9]*\(.*\)$/\1/p' | sed 's/^[ \t]*//;s/[ \t]*$/"/' |\
sed -n 's/\(.*\)/"\1/p' > newfoo

Sample output from above now appears as output below in file called newfoo:
"/first/Big/Directory"
"/second/big/Foo Junk"
"/third/big/Dir"
"fourth/big/Dir_ectory"

Based on the file newfoo above, how can I cd into each of those directories and gzip the contents ? Everything I try ends up in messages basically stating that it can't find or stat the directories. Any suggestions or help would be appreciated.