Article: Both the leaves and the stems of poison oak contain urushiol, an oily plant substance that triggers an allergic reaction in the form of the poison oak rash. Urushiol can also be found in the roots and even in the dead plant.  In addition, urushiol can become airborne if the plant is burned and is easily transported from one object to another. The rash from poison oak is not contagious in the standard sense, but if someone has the urushiol on their hands and touches another person, that second person can react as well. All parts of the poison oak plant contain the toxin urushiol. Even when the leaves fall off in winter, the plant is not safe to touch. A rash from exposure to poison oak can vary depending on the person because some people are more sensitive to urushiol than others. In general, the rash will be very itchy and very red, with red bumps that may blister and ooze fluids. The rash can be streaky and patchy and can range from relatively mild to very severe. When you are exposed to poison oak, first rinse off any exposed area with soap and warm water as soon as possible, hopefully within 30 minutes. Also wash any clothing or tools that may have been exposed to the plant. In order to help relieve the itching of the rash, apply calamine lotion to the site. You can also apply topical steroids such as clobetasol or systemic steroids and antihistamines. Also try a cold compress or an oatmeal bath.  To make an oatmeal bath, pour two cups of oatmeal into a nylon sock or stocking and tie it onto the tap so that warm bath water runs through the oatmeal.  Soak in the tub or soak the affected areas for at least 30 minutes. You can also use baking soda in a warm bath. Be aware that urushiol can be easily passed to another person, animal, or object. Make sure anything or anybody that may have come into contact with poison oak is carefully washed with soap and water. Most rashes will heal in five to 12 days, but the rash can last as long as a month or more. Call emergency services if the reaction to the poison oak is severe. You should also call is you or the infected the person has trouble swallowing, breathing, or has severe swelling at the site of contact or anywhere on the body.
Question: What is a summary of what this article is about?
Learn what causes the rash. Recognize the rash. Wash your skin and clothes. Relieve the itching. Keep the rash from spreading to others. Seek medical help.

Once you've installed a new catalytic converter, one thing you'll want to do immediately is double-check to make sure there aren't any leaks in the exhaust system on either side of it. Depending on where it is, an exhaust leak can cause a variety of problems for your vehicle, including reduced fuel efficiency and long-term damage. There are several ways to find an exhaust leak. One is to simply be observant while you drive — if your car sounds louder than normal when it runs or seems to "rumble" more, you may have a leak. You can also check for leaks by jacking your car up, starting it in park, and carefully moving a lit candle along the length of the exhaust tubing. Leaks which are invisible to the eye should cause the flame to waver or blow out. One problem that can occur in faulty catalytic converters is that they can become "backed up" with soot, debris, and other exhaust byproducts or broken apart inside the converter. In this case, the engine's ability to rid itself of exhaust is hampered, which can cause a vehicle's fuel efficiency to plummet and can even cause the engine to stall in severe cases. Luckily, performing a backpressure test is simple — just screw a pressure gauge into the oxygen sensor's hole before the converter in the exhaust manifold in most vehicles. The pressure reading should be less than 1.25 psi when the vehicle's engine is running at 2,000 RPMs. The worse the congestion is, the higher the pressure reading can be. Very bad backpressure readings can approach 3 psi. If your car's converter is old and worn, one simple test can tell whether it needs to be replaced very quickly. Simply grab a rubber mallet (or similar tool) and give the converter a firm hit. If you hear any sort of rattling, your converter needs to be replaced — this indicates that the metallic catalyst within has begun to corrode and crumble.  However, if you don't hear a rattle, this doesn't necessarily mean that your converter works well. There may still be other problems with it. To be clear, this test can only tell you if you have a bad converter, not if you have a good one. Catalytic converters can be tricky parts — if you're in doubt about whether or not yours is functioning properly even after performing the tests above, don't hesitate to take it to a mechanic or specialist. These professionals will have access to the type of equipment that can be used to perform more advanced tests, like delta temperature tests, oxygen storage tests, and CO2 tests.  Most auto shops that offer smog testing will be able to perform these sorts of emissions tests.
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One-sentence summary --
Check for exhaust leaks. Measure back-pressure in the exhaust system. Perform a mallet test for old converters. Consider more advanced tests.