Never a bother - every question asked means another opportunity to learn something new. From what I've gathered, using detergent and lots of water should be sufficient to remove the oils. I'm including some links (don't say a lot about it except use soap and water):
For the last 10 years, we've done the minimal approach and have never had an issue (should I be knocking on wood? I don't know). If we walk through a patch of poison ivy, we just hose off the shoes with water or walk through some tall grass or rub in dirt. I'm not advocating those methods - just mentioning what has worked for us so far.
It's not likely that the oil will soak into the leather and be an issue for you. A good wash down should be all you need. Leather cleaners won't give you any more "cleaning action" than a good scrub with soap and water will. These are soaps of some sort with added conditioners or milder detergents to prevent damage to the leather.
Your boots should be good to go.