Another project is growing large salt crystals in saturated solution.
The Unitech Electric Static Wand Toy off amazon was also popular last year (poorly built mini Van de Graaff generator.)
Glow in the dark wall paint and a 5 second strobe light is also a classic silhouette demo.
Could also look for linear polarizing sheets, thermochromic sheets, and "Magnetic Viewing film".
Some will like this stuff, others only want to stare at a screen. =3
The photographic steps are pretty accessible.
It's not lithography, but you can build a working processor out of small surface mount chips, and you can solder these chips with lead-free solder. That seems very achievable for a motivated engineer, and probably involves much less toxic chemicals?
But maybe the easiest way to do (very low resolution) photolithography at home is to use dry film photoresist, which is like tape you can stick onto a copper PCB you then expose and etch; a cheap roll is ~$20 from eBay/Amazon.
[1] https://docs.hackerfab.org/home [2] https://dspace.mit.edu/handle/1721.1/93835 [3] https://www.inchfab.com/