Standard non-read-protected EPROMs? Back the things up onto stable media ASAP (get a professional to do it if you are not technically minded or not familiar with handling computer chips), and store the original chips as per rickhunter's advice. As long as you keep the original chips, it is 100% legal to run a backup containing the exact byte-identical software in your machine (IANAL though, not all countries are "free" when it comes to fair use). It is nothing short of scary that people are still using factory original erasable-by-design chips that are pushing 50 years old, with no plans on what happens after the chips suddenly fail. It's a lot less painful to accidentally destroy a newly-burned EPROM than a 40 year old factory EPROM that is extremely rare and expensive to replace, if you can even find one at all.
For read-protected ROMs and suicidal chips (e.g. VLC setchips, Konami iButton devices etc.), follow rickhunter's advice but keep them well away from any form of backup device, and good luck if they still even work after 30 years (case in point, the arcade scene with self-destructing machines from the likes of Sega, Capcom, Gaelco etc.)
Additionally, do not, under any circumstances, insert a slot machine CF card or hard drive or whatever into a Windows PC, unless you want to brick the slot, as Windows will happily write stuff to the device the instant you insert it, even if it cannot read the file system due to being EXT2 or whatever.