How do I clean the oven really well?
Don't use alcohol to clean an oven.
If your oven has a "self cleaning" mode, try that.  It basically puts the oven on full blast (2-3x the normal baking temperature) and "burns" all of the crud out.  Sometimes there will be some charred stuff behind that you have to wipe out after it is done (see #3).  Because of the extreme temperatures involved, there is usually a safety latch on the oven door to lock out the self cleaning mode.
Use oven cleaning spray.  Easy-Off is the most popular example of this.  You spray it on, wait a few hours, and then wipe it out with a damp sponge (follow the instructions).  All of the crud in your oven will turn into a brown sludge that just wipes away.  Be warned, oven cleaners are extremely caustic.  Use rubber gloves, and don't rub your eyes while you are working.  The fumes are nasty too.  They have newer low-odor ones, but they can still make you gag.


Option #3 will make your oven look shiny and clean.  However, it takes a lot of manual labor to get it looking good.  Might take more than one cleaning session.