How to combine aluminum with copper if the old compound is oxidized?

Hello, since I don’t really understand something about electricity, and when I’m young, I need help. I live in a private house, a couple of weeks ago a light began to flash in the first part of the house, and later the sockets stopped working, everything is in order with the second part of the house. He climbed onto the roof, began to look for connections and a distribution box. In the cable connection that goes from the meter to the house, it is oxidized, as well as in the distribution box (aluminum to copper connections). Everything is connected there due to twisting and electrical tape. After reading on the Internet I came across the fact that it is undesirable to twist, that it is better to use terminals (I did not find self-clamping and lever in my city). I also did not see the pads of black plastic with clamping plates, basically what I met was the plastic terminals (but I read that aluminum can not be clamped). I thought I could just go over the wire cutters in a new twist and cover it with insulation with a heron (heat shrink or the same insulating tape). I will be glad to any advice, thanks in advance.