How do EVs work in Generation 1? How to avoid changing the Pokemon’s Special stat

I've been messing around on this old VC save of Yellow. I wanted to dupe some X SPECIALs with missingno to perform another glitch. I tried a few times, each time with a different oversight in the process causing me to fail. I haven't played in a long time. When I finally got it, a Gloom appeared instead of missingno, because my Pidgeot's Special had risen to 186, index no. for Gloom, because I had put Pidgeot in a box and removed him with some Effort Values on him from some wild encounter. Using a stack of rare candies, I got Moltres up to Special 181, but I'm worried about the same happening to him. How can I avoid Special EVs or remove them in a relatively simple manner to avoid changing Moltres's Special stat? The only Pokemon I need to encounter is Ditto and Ditto transformed into Moltres, and I don't even need to attack, I can just run. Any help is appreciated, it is surprising how little information on EVs before Gen III is readily availible on Google.

Best Answer

There is no particularly efficient way to remove EVs in Generation I titles - no doubt there's some glitching you could possibly do, but the process is likely so long and convoluted as to be nigh useless.

To avoid gaining EVs in your Special stat, simply do not feed Moltres any Calciums, and do not have Moltres defeat any Pokemon (or participate in a battle where one is defeated). If you have the EXP. All, dump it in the PC since it spreads EV gains among the party.

It is noteworthy that I don't include a list of Pokemon to avoid -- for good reason. Unlike later games, in Generations I and II, a Pokemon gains EVs, not based on preset values tied to the species of the defeated Pokemon, but based on the species' base stats. So, for example, if you beat a Mew, you would get 100 EVs per stat (since Mew has a base stat of 100 in each stat). No non-glitch Pokemon have zero in any base stat, so Moltres cannot be allowed to KO a Pokemon whatsoever. (Or participate in defeating a Pokemon, or gain EXP. from the EXP. All, or whatever.)