I don't want to create deb package. I have a deb, i want to extract it and install the package into the system by copying it into the proper directories.

I tried extracting and copying the files into /
I also copied the files in DEBIAN folder into /var/log/dpkg/info with appropriate name, also pasted in the .list file.
But it doesn't work. Some apps are usable if done like this (some don't work, like dropcache-free all always says no visible effect, devel-su says can't set groups), But I cannot uninstall the packages later. I cant even list it using dpkg -l.
So are there any files that dpkg modifies which i have to by hand for this to work?