I have asked a similar question before:
I can almost not use my BBB any longer, due to lack of memory.
Does other Angstrom-users have the same problem?
I can store data files on my micro SD-card.
But I do not know how to install programs the SD-card. They are always installed on eMMC card.
I would also like to know how to delete one of the pre-installed applications, such as GIMP?
And yes: I have deleted all the LOG-files etc.
Greetings Poul C
If you don't need X, you can reclaim space by removing x11-common. I
like to run on the eMMC myself, mainly because I keep loosing the micro
SD cards 
I recommend looking through the installed packages and removing what you
don't need. There is a great Debian wiki page on how to do this:
https://wiki.debian.org/ListInstalledPackages .
This command also appears to work as well:
dpkg-query -Wf '${Installed-Size}\t${Package}\n' | sort -n
Lastly, I've seen recommendations to install the wajig package to
determine the size of all packages installed. However, it takes about
14.4 MB:
The following NEW packages will be installed:
python3 python3-apt python3-minimal python3.2 python3.2-minimal wajig
0 upgraded, 6 newly installed, 0 to remove and 60 not upgraded.
Need to get 4,514 kB of archives.
After this operation, 14.4 MB of additional disk space will be used.
Do you want to continue [Y/n]? n
Ironically, you may not have enough space to install this package 
Josh
Sorry, I just realized that you an Angstrom user...
I'm not sure about package management in Angstrom, good luck
I’m sorry about the double posting…
/Poul C
If you register, the double posts won’t happen.
Gerald