Two good uses for too many lemons (or any other citrus fruit for that matter). We have a lemon and lime tree, and even after giving them away like crazy we have too many.
Wash. Slice 1/4" thick. Line them neatly in layers in a large clean sealable plastic or glass jar or other container. Between each layer sprinkle a few teaspoons of coarse kosher salt. Use plenty of salt, there is no such thing as "too much" for this, but too little can be a problem. When the jar is pretty much full, put a potato masher or similar tool in there and press. If there isnt enough juice to cover all of the contents, juice a few more of whatever citrus you're using and add the juice to cover. Seal jar airtight. Put it on the counter for about 3-4 weeks, gently shake the jar once a day or so. Add a half to one inch of olive oil and refrigerate for up to one year. It should look like a bunch of sliced lemons floating in juice. If any funny colored stuff shows up inside or on top, you didnt use enough salt. I usually put 1/4 to 1/2 cup of salt in a half gallon plastic container.
This will sound a lot more disgusting than it is. The pulp turns jelly-like and the rind softens. The entire thing is edible but...do not...I repeat...do not...eat any of this plain. Chop them up and add to Tagines or other stews where they'll slow cook a while and you want a lemon/lime/orange/grapefruit and salt flavoring. Place inside a cleaned fish or on top of a filet. Stuff inside a chicken. The entire thing becomes edible in a stew...discard after cooking in any other application.
For the ones you're just juicing, use a very sharp potato peeler or zester to remove the zest before cutting in half and juicing. As much of the colored part of the peel and as little of the white pith as possible. Drain off some vodka from a new bottle. I'm sure all y'all can figure out what to do with the drained off vodka. Nothing fancy needed here, I use smirnoff. Add the zest. Over time, you can continue to add more zest. Shake the bottle once a day. After about 2-3 weeks the vodka will take on the color of the zest and the zest will lose its color. When its bright yellow/orange/green depending on the citrus you used (about a month), pour it through a cone coffee filter (or other fine filtration device you want to fool around with), clean the bottle, replace the citrus vodka back in the bottle, add a quarter to half cup of sugar. Shake until the sugar dissolves. Freeze and drink neat or over ice. The lemon growing region of Italy calls the lemon version "lemoncello" or "limoncello". Unfortunately more than one or two shots of it and you start feeling like you're drinking furniture polish.