I do not recommend using the products you mentioned. Bleach? no way this will harm the adhesive in the decal. Ammonia in windshield fluid is bad for decals too. Soap and water can work but if you use too much soap or the wrong kind the decal will not stick or if you use too much water the decal will not slide. Either way now your decal is junk.
Use a product my company manufactures called "Sticker-On!" Decal Application Fluid. This proprietary formula allows you to slide and position your decals into place and then does not interfere with the bonding of the adhesive in your decal. We sell gallons and gallons to the Nascar guy's. I will be using some this weekend as I prepare my boat for the Catalina Ski Race!
Go to www.hardlineproducts.com any questions you can contact me personally.