A good tomato is a terrible thing to waste, but canning can seem like such a sweaty chore. Luckily, The Kitchn has a quick and super easy way for preserving them without any heat: freezing.
Photo by Vladimir Morozov.
The link below can walk you through the whole process, but all you really need to do is clean, core, and pop the tomatoes in a freezer bag, where they will keep for up to six months.
When you're ready to use them — for sauce or soup, not sandwiches — just let them thaw for about an hour, then peel the skin away.
How To Freeze (and Thaw) Tomatoes [The Kitchn]