

If you haven’t needed them for such a long time, they probably weren’t all that important anyway.
Same goes for all the physical items in my home. If I haven’t needed something in a long time, there’s a good chance I never will. This is how I reduce digital and physical clutter in my life.

Other people have already given sensible suggestions, but I’ll mention one group of chemicals that can damage your phone: bases.
If your phone has aluminium parts, highly concentrated bases will begin to gradually dissolve them. Hopefully nobody was thinking of using dishwasher tablets to make a soap solution for your phone. That’s a bad idea, since the resulting solution has a very high pH-value (base). What about the powder used for washing clothes? Same thing. Even regular hand soap is basic, but it’s nowhere near that extreme.
Exposure time also matters. If you just wipe the phone with a damp cloth, the time will be very short. If you really want to damage the aluminium parts with hand soap, it’s going to take an absurdly long time to do anything. However, those dishwasher tablets are a different beast.
Temperature matters too. These kinds of reactions happen faster if you heat up the solution.