Do you not know how to make soap?
Soap is oil + sodium hydroxcide
It isn't one or the other.
The goal is to remove the oils from your skin. Not smear them around. You need soap specially designed for removing oils, such as dawn. A normal soap will not achieve this.
Rubbing alcohol doesnt hurt your skin. Lol. Its easily better than 2 weeks of dermatitis(poison ivy rash).
Cold water is more effective at removing the oils from your skin than an oil based soap is, and I believe you may be confusing the effect. You may very well achieve 90% this way, but you aren't EVER going to get the job done as well as 30 seconds of rubbing alcohol would.