I remember being a big fan of the original Master of Orion and Master of Magic... so when Master of Orion 2 came out, I instantly bought it.

I remember in that first version I bought, you could actually turn toxic worlds into barren worlds and then terra-form them. Is this something that was changed in a later version? As best as I can recall toxic waste dump technology allowed you to do this, but it's been awhile.

Does anyone else possibly remember anything like this?

Toxic Waste Dump eliminates all pollution. That was always its effect.

Toxic Worlds cannot be terraformed. The only method I know of getting rid of them is to gift them to the AI, use a stellar converter on them (turning them into an asteroid belt), and then getting another planet in the system to reconstruct the planet, resulting in a Large/Abundant/Barren.

Honestly, that's not much of a solution. You would lose mineral resources if there are any, or gold/gem deposits or artifacts research bonus possibly. I just remember it being different, and I'm wondering if that was something they changed with later versions of the game(I know certain things changed, like the custom race picks changed as the game was altered for later versions). I do remember an early version, possibly the first, where we turned toxic worlds into barren worlds.

I dont remember anything like that when it came out. Maybe you are thinking of radiated worlds? When you use a radiation shield or higher it turns to barren. The way mentioned before is the only way to make it happen.

It was so long ago but I cannot remember toxic ever being terraformable in MoO2. I think I even reacted to it being one of the changes as compared to MoO1 where radiated was the worst and that one was terraformable.

Nah, I wasn't pointing it out as a solution. It's just the only way to get rid of Toxic environments in MOO2. Toxic isn't actually meant to be terraformed at all; the method is accidental. You need Planet Construction tech, end-game Stellar Converter tech, there needs to be another colonizable world in the system, and your race can't be Repulsive. Hohiro points out that planetary shields convert a Radiated environment to Barren. Were you thinking of Radiated?

They can, actually, by the climate change random event.

In MoO 1, any hostile planet can be changed to "Minimal" climate via "Atmospheric Terraforming" technology. This increases the max pop and removes the "Hostile" growth penalty. "Soil Enrichment" changes planets that are at least "Minimal" to have higher max pop and "Fertile" bonus. "Advanced Soil Enrichment" changes planets that are at least "Minimal" to have higher max pop and "Gaia" bonus. There's also "Terraforming X" which increases the max pop by "X" (i.e. Terraforming 30 will increase the max pop by 30).

However, in MoO 2, this mechanism has been radically changed. There's no longer "Terraforming X" technologies. You no longer need "Colony Base" technologies to settle radiated/toxic/other hostile planets. There's only a few ways of increasing the planet's max population limit, such as Biospheres, or by improving the planet's climate. But "Toxic" planets cannot be terraformed aside from blowing it up.

Each of the games in MoO series is very different from each other. MoO 2 isn't a straight successor of MoO 1 like Civilization 2 was to Civilization 1. A lot of game features changed (food introduced, stacked ships removed, etc)

Which is why players with wide taste in games might very well have all MoO games installed simultaneously.

Just use androids on toxic worlds...

This. Androids are tolerant and so ignore both the toxic atmosphere and pollution.

Pollution on Toxics is no different than on other climates, the difference is that on a Toxic world you pay 50% extra in maintenance cost, which is still the case when you fill up the colony with Androids.

Note that under 1.50i rules, Toxic planets can be terraformed to Barren ones, no more need to give such colonies away and 'Stellar them'.

I always wondered about this and seems like maybe the answer is here in this thread.

Build android workers on toxic planets.

I have looked at the android workers and my analysis was that they weren't worth it.

But, on toxic words...

I will have to try that.

Just a note, as far the vanilla game is considered I don't think you lose mineral bonuses by blowing up a planet, at least asteroid belts with hidden bonuses can exist.

But yeah, that is a thing you only do long after you are already won the game and just play simcity.

Actually thats not really useful, but curiously also not entirely wrong info, assuming "vanilla game" as a some staple version like a v. 1.3 and later, and not some possible obscure early version. Technically you indeed dont lose a mineral bonuses by blowing up a planet , though you do lose a bonus planet special this way; and while asteroid belts with hidden bonuses can technically exist, they shouldnt do it according to an actual game rules (they cannot be generated this way, and they lose a bonus if created from a planet) (while can do it with some memory manipulation, say save editor or some other game data corruption). You would lose a mineral bonuses (actually "values") on a building an Artificial planet tho. So, while sentence " you [don't] lose mineral bonuses by blowing up a planet, at least asteroid belts with hidden bonuses can exist." is actually true, its really misguiding as a proposed contradiction to:
as its technical (though useless) correctness contradict the actually discussed game event from player's POW : in game reality you lose both mineral bonuses and planet specials via blowing a planet up with Stellar Converter and rebuilding it with Artificial Planet (while its also true what its possible to do various stuff with memory editors).