Yes, you can use a chemical stripper that contains methylene chloride. Urethane finishes are more chemical resistant than standard oil products so the aggressiveness of the methylene chloride is needed. Follow the directions on the label and the finish will be easily removed.
If using methylene chloride stripper, please follow ALL the safety warnings on the can.
Eye protection is a must, it can easily blind you. I recommend a full face shield type as opposed to goggles, but both would be better. Safety glasses with side shields under the full face shield may give you better vision.
Have a source of running water handy to use for flushing any that gets on you. (That means a water hose that is already turned on with just the nozzle shut off. Best to use a trigger type nozzle, as gloves slick with the stuff make it hard to turn on a twist type, expecially when you can't see) If it does get in your eyes, flush them well with water immediately for 5 minutes before you even call a doctor or seek medical attention. For skin burns, treat them based on their severity as you would any other chemical burn.
Protective clothing is a must. It will burn you. Use heavy duty rubber gloves. Latex or Nitrile surgical gloves won't cut it for this stuff. Get long gloves and roll a cuff in them so it does not run down them onto your arm.
Ventilation or respirator is a must. It will burn your lungs and respiratory passages.
For best results:
Do not flush the item with water to neutralize the stripper until you have all the coating loosened. Otherwise, you will have to let the moisture dry before starting again. A thick wet coat of it works better than a thin one, but it may only take off a layer at a time, so it may have to be scraped or agitated with a stiff brush or matt several times. Just reuse the goop scraped off the first layer to go back at the second layer until it quits working. Poly or oxidized coatings will bubble. Lacquer will just dissolve.
I used this stuff extensively while working on aircraft and parts. It is a nasty customer. However, it is effective and may be the best alternative for some coatings. I have gotten it in my eyes and am not blind (flush quickly and thoroughly. It kinda feels like someone putting out a cigarette on your eye ball).). I am not saying don't use it, but please respect its toxic qualities.