I do a lot of canning whether it's leftovers or something I set out to especially can like the salsa last weekend. I thought it would be nice to pass on a few tips on the way I do things in case it would help someone else.
Most everything gets done in the pressure canner as it won't heat up the kitchen like a water bath will and because I mostly can meats, broth and vegetables. The salsa was pressure canned too even though tomatoes can be water bathed because they only process for 10 minutes under pressure and these days unless you know the tomatoes are heirloom there's no telling if there is enough acid in them to make them safe for water bath canning. Better to be safe than sorry.
I start out with running my canning jars through a rinse cycle in the dishwasher to make sure they are freshly clean. When that's done the jars go in the canner and I fill them with water and put several inches of water in the canner as well. For some reason if the canner is not at least 1/2 full with water it will go dry if I am processing for the longer periods. You don't want your canner going dry as it will warp it and they are a bit pricey to replace.
I turn the heat on under the canner and also heat up on another burner whatever food is about to be canned (unless it is a cold pack item). On a small burner I heat a saucepan on medium to heat the lids. If you have a variety of jars you may have wide and regular mouth in the same batch. If you alternate the size lids in the saucepan they won't stick together so badly. Also lay out the rings in easy reach.
Once everything is heated and the canner is boiling, remove one jar at a time using a good jar lifter like this:
The coating helps grab the jar securely around the neck and the wood handles make sure your hands don't get burned. Dump the water from the jar in the canner or a bucket (use it to water plants, etc. once it's cool.) I add a 1/4 to 1/2 a spoonful of citric acid to help preserve the color and to add that acid content, it adds no flavor.
Fruit fresh is the easiest one to find, you can also use it to keep your guacamole from turning brown. Sometimes I add a bit of salt but usually not. Using a canning funnel I add the food or broth by cupfuls. I use a teacup, some folks prefer a measuring cup or ladle but for me a ladle is an invitation to a mess. Use a wet paper towel or cloth to wipe the rim of the jar, it must be totally clean or it may not seal. One of those handy magnet sticks for canning is great for getting the lids out of the saucepan and setting it on the jar.
Then screw down the ring firmly. Sometimes using one of those grabber pads helps to hold the jar still without burning your hand.
Some folks also use kevlar gloves. Look for them in the stained glass section of the craft store as they are priced cheaper than the ones you may find in a canning section of an online store and they are the same thing. They look like knitted gloves in off white. I use some when I am soldering the saint pendants I make.
Put your jar back in the canner and repeat till all jars are filled and proceed as usual with the canning.
Once your canner is cooled down and pressure is released, take out the jars carefully with the jar lifter and set on a folded towel or even a 4 layer thick tablecloth. Leave a bit of space between them. They will probably still be boiling inside, that's normal. Then comes the best part, listening for the lids to pop or ping as they seal! If you have jars that don't seal put them in the fridge and re-can or use right away.
Once cooled, remove the rings. If you leave them on they may trap food residue or moisture and rust which could loosen your seal and make the food go bad.
Now it's time to wash the jars in warm water with a bit of dish soap. I have hard water so I add a couple glugs of white vinegar as well. Wash especially around the neck to remove any food residue that might be lurking.
Once dry I label the lid with contents and date and store in a dry, cool and dark location. Definitely make sure it is dry or the lids could rust and you would lose the food. Canned food will last pretty much indefinitely though the color and texture will degrade. Some say the nutrients will degrade over time as well but if you are hungry you will find a way to use it.
A couple other opinions on lids and rings. There are reusable lids from Tattler and I have one box I picked up at the resale shop. They do work well but read the instructions carefully as it is a bit fiddly to get it all on properly. Also, the last 2 times I had to buy new jars at Walmart, all they had in pints were the Better Homes and Gardens brand.
While the jars are pretty with their lattice pattern, they come with a gingham lid and a white painted ring. You will notice that I did not put the white rings on the gingham lids. If you do they will stick to the point you have to cut the ring off. I found out that the first time I used them. The white rings will stick no matter what and you will have to use the gripper to remove them. It's sad because I was hoping the white lids would have less chance for rusting, but I really don't like them. They can even stick with the plain lids but not as bad.
Tips on buying jars:
When possible go to garage sales and thrift shops to find jars, they are much cheaper this way. You can also safely use mayo or sauce jars as long as the lids and rings fit properly. I have never had a problem reusing these. At the worst you could get a cracked jar and just lose that jar's food and have a little mess to clean up. But I have had that happen with regular canning jars on rare occasions. Discount and dollar stores are a good source too, Big Lots carries jars nearly year round here in Texas. If buying second hand, run your finger over the rim to make sure there are no chips as that will cause the jar to not seal.