Since this thread just got unlocked and the auto-lock lifted, I figure I’d throw in a couple answers from my experience 
The trays are probably good. When I got my “time capsule” 1+, I got one (Rev1) tray full of resin wrapped in foil that’d spilled all over it, one brand new (Rev1) tray with its protective wrap still attached, and one “Form 1+” amber tray in the upgraded 1+ that hadn’t yet been opened/used. Here’s what I learned from those trays:
The Form 1+ amber tray works flawlessly. I use it exclusively with genuine, new Form 2 resin, for work projects where they have a Form 2 that’s frequently “over-booked”. I pour the Form 2 resin into the tray, and select the proper version from the PreForm 2.20 interface. Prints always come out perfect.
The Form 1 (Rev1) trays are another matter, but probably because I abused them. The foil-wrapped one was a total loss. To clean up the spilled mess, I scraped off much of the resin into a junk IPA container, then ran it through a Form Wash cycle (it fits in the Form Wash in its entirety!). It came out clean, but next time I went to use it, well… the PDMS layer separated from the acrylic and I’m like “oh… ahem, right, I’m dumb”. Don’t wash the tray in IPA. It developed micro-cracks all around the edges, and because it gets a big succ applied when peeling layers, it let some resin between the tray’s layers and gave a big “game-over”.
The second Rev1 tray I used for experiments with cheap resins. This is where I learned that DLP resin (at least, Anycubic resin) is way, way, way more light sensitive than laser resin. It cures like glass, fairly brittle. Oh, and it sticks to the bed like glue. Literally glue… it tore a nice chunk out of the bed. Thankfully I only had a small part, but that little chunk left a big burned ring around the area it was torn from. The OpenFL version of PreForm lets you do custom profiles, but I couldn’t quite get it dialed in.
As for resin, I got 4 bottles - 1 unopened grey, 1 unopened black, 1 unopened clear, and 1 partly used clear. All of them are junk. Even with tweaked exposure settings, and even with experiments with unexpired resin mixed with the expired stuff, I’ve not been able to get any satisfactory prints out of that resin. Of course, I tried mixing the absolute hell out of it. No amount of mixing or light warming seems to do any good. It’s all garbage. Mixing it seems to have the effect of “if you add any expired resin to the mix, it just decreases the quality and increases chance of failure”. So I’m just working on curing it into solid cube blocks with a tweaked OpenFL material profile, so I can discard the stuff. (update: only the black resin could even be cured at all; the clear and grey stuff is totally “incurable” and stays liquid no matter what exposure seems to be applied. I didn’t feel like risking higher than 62mW or lower than 500mm/s… it wouldn’t stick the first layer to the bed, nor leave any cured blobs in the tank. It’s a total loss)
To make up for the lack of a heater, I removed the screw-on rubber feet from the bottom of the Form 1+ and I set the printer on top of a heated bed from a Lulzbot Taz 5, and hooked it up to a power supply feeding 7 to 9 volts DC to it (a 24v bed). It keeps the printer and resin comfortably warm in our cold (un-heated) office area. I recently learned that there are heater mods that might be easier to maintain inside the unit, and will probably go for one of those instead. Heating is important, a lesson they probably learned after the Form 1 design (the Form 2 has a resin heater that its firmware is fairly insistent is quite important - so I copied the idea to the Form 1 before even starting a print).
Now, there’s aftermarket trays (Z-Vat) and aftermarket resin (ApplyLabWork) available to keep the 1+ running happily. The OpenFL version of PreForm (v2.3.3) seems to be a significant upgrade over the 2.20 version which was the last one to officially support the Form 1+, particularly in a bug that makes v2.20 use 100% of a CPU core all the time, fixed in 2.3.3. Odd, though, that v2.3.3 doesn’t seem to support Form 2’s Grey v4 material, so I have to go to 2.20 to get recognized support for that material. Maybe I could just use the Grey v2 profile and it’d work OK, but I haven’t wanted to test my luck there quite yet.
I also just learned about the Prusa CW1, which would be an incredible companion to a Form 1/1+ as a more cost-tolerable alternative to Formlabs’ Wash and Cure machines. I have access to a Wash and Cure set at work, but many others may not, and it really helps realize the excellent quality of the aging Form 1+. (https://shop.prusa3d.com/en/accessories/720-original-prusa-curing-and-washing-machine-cw1.html)
tl;dr:
- You’ll need PreForm v2.20 (PreForm older versions) to touch the printer, or OpenFL (https://github.com/Formlabs/OpenFL/#preform) to be able to “touch” the Form 1/1+, as newer versions give a confusing error about an “unavailable printer” due to not being supported.
- The trays are probably good, just don’t cook them in IPA.
- New trays are available, Google Z-Vat.
- Don’t use expired resin, it will only result in pain.
- Form 2 resin is totally compatible, just unscrew the cap and pour it in, and cry as your expensive Form 2 compatible cartridge chips go to waste. (maybe sell on eBay? They do seem to sell regularly)
- New cheaper Form 1+ compatible resin is available, just try finding Formlabs resin on Amazon and you’ll find ApplyLabWork’s compatible clones.
- For the love of god don’t use DLP resin
- You need heat. Heat the resin somehow. Heater mods may be available but I use a Taz 5 heat-bed to warm mine.
- Washing and curing is a pain in the arse, if you don’t have a Form Wash/Cure set, Prusa’s CW1 is pretty comparably nifty at half the price.