remove .deb package and install previose version

["Oleksiy \(alex\) Bolgarov" <axb@myna.com>]

Hello, debian users!

Does somebody know how can I remove .deb package and install
previouse version of the package?

For example, if I installed package from unstable distribution,
but an not satisfied with it, and want to return back to the
same package from stable distribution?

I've removed the package using dselect, and removed lines
in apt configuration file (/etc/apt/sources.list/) that 
point to un-stable distribution, but anyway when I start
dselect, it shows me version of the package from unstable
distribution...

alex