Did it as chaosmonk suggested.
Tried to run this script from lubuntu 16.04 LTS. The script is probably too
old. It removed a lot of packages, but broke the system. After a reboot there
was still lubuntu artwork and LXDE environment, any trace of trisquel.
Lubuntu booted after this script, however non functional, because lots of
packages ar gone.
If somebody is interested what went wrong, I have copied the trisquelize log
here: https://pastebin.com/sk6a6p1i
It would be nice to have a working script like this.
Anyway, I need no further help, because after this failure I decided not to
waste my (and yours) time and installed a fresh copy of trisquel onto that
computer. It's working fine now (and, most importantly - free).
Thank you guys for support!
