Regular oil in Morse machine?
 

My father in law was "helping" me and he oiled my mom's sewing machine for me. I think he used WD40 or something like that. Is the machine going to be ruined? I set it up and was about to use it in December and I got a shock so I need to get it rewired. It's been sitting in my garage since then unused. If he used cooking oil or something will it be frozen when I try to use it? I don't know why he even touched it....

If it's a machine you really care about, take it to a reputable sewing machine repair place and they can clean it up for you if necessary.

As to "why" your FIL messed with the machine? If he's basically "good" - he was trying to be helpful.

Oh yeah I know he was trying to be helpful... I am just frustrated :) I know he would never do anything to me on purpose to hurt me... he is better to me than my own dad :)

Clean that WD40 out of there.

The machine has to be thoroughly cleaned inside. Only sewing machine oil can be used on sewing machines. It is a much finer grade of oil than other types. WD40, cooking oil, etc. have to be cleaned out of the machine.

If you're taking the machine somewhere to get it re-wired, I would explain the situation to them and ask that they clean and oil the machine for you while it's there.

Use Liquid Wrench to clean the machine joints and everywhere he put the mystery oil, wipe clean and then oil with sewing machine oil.

Before you do anything, ask him what it was he used. Pat M gave you some good advice, use Liquid Wrench to 'rinse' away whatever it was he used. And then use sewing machine oil.

If it was WD-40, I wouldn't worry too much. WD-40 evaporates away anyway. It's does a temporary job at lubricating, which is why you don't find it listed as recommended in manuals for sewing machines, lawn mowers, tools, machinery of any kind, etc. There are properties in it that retard rust, which is why I coat my gardening tools with WD-40 before storing them away before winter. But it's worthless as a lubricant, it evaporates within a month!