Homebrew PCBs

How do you coat the copper traces to keep down the oxidation and 
improve solderability?

I haven't made a PC board in 25 years, but back then, we put the PCB in 
a solder bath with a peanut oil top layer to keep down the dross.  This 
was time consuming and costly (solder was expensive in that quantity).

How is it done today?  I saw some mention of 'tin-it' in one of the 
threads here but cannot find it on the web.

This is a great group and it's quite interesting comparing how home-
brew PCB's are done today and how we did it 25 years ago.  Isn't 
technology great?!!

Thanks in advance,

Jim