The only model I've modified is a Firespray that I gave Kath Scarlet's scheme on. It looks okay but the more I look at it, the more I find that it could be much better.

So is there any good safe way to strip the paint off of a model?

I've heard a couple ways, but honestly it isnt needed, and the original makes a good base coat..

I have done many repaints and never stripped any of them.

Thin your paints and use a couple coats and it whould be fine.. post up a picture of your Kath repaint and let us see what you've done with it.

Painting over the FFG coat is fine it's super thin. You'll probably lose detail painting over what you have painted though. Simple Green is what I use, won't wreck the model or your hands, takes about a day or so of soaking.

I stripped one of my Firesprays in brake fluid with not problems at all. A couple hours and the paint scrubs right off.

Tamiya laquer thinner works great for me

I do use an alcohol based hand sanitizer ( https://en.wikipedia.org/wiki/Hand_sanitizer ) called 'Sterillium'.
Sterillium is a German hand sanitizer and you can get it for real cheap in any German pharmacy/drug store.
But I suppose you can get an equivalent in every country.

Great thing about it it: it doesn't affect the plastic models but still removes acryllic paint really nice and you don't have to worry about your hands getting in contact with this stuff.

Just get a bottle, place your mini with the liquid in your sealable container of choice and leave it over night. Grab it from the containter and use a toothbrush to brush of the paint. Done.

Now it usually doesn't get all of the paint off. I did have some remaining black paint around the recesses of my A-Wing's laser cannons for example but since I tried that stuff with my warhammer minis a few years ago I don't think there is any better solution for stripping paint.

*** Advice for dummies: Don't drink it! Prodect your eyes with goggles when brushing. ***

I've tried Simply Green, which took off the wash, but left the paint untouched. And then I went and used brake fluid. I used it on 2 X wings and 1 Y wing... But quickly came to the same conclusion everyone else has - you don't need to strip the paint. Someone was trying to convince me I did, so I pulled out two of my repaints, and said "one has been stripped, the other hasn't" and he picked the wrong one. We did this 3 times, and he picked the right one once, which means that he was randomly guessing.

However, I did have an experimental paintjob go wrong and ended up with a really thick section of my paint that I needed to strip and restart, and brake fluid once again came to the rescue. It sounds like you're trying to undo what you already did, so that would be similar to what I had to do. And brake fluid worked great. Note, I don't because I'm stupid, but please wear gloves when handling this stuff. It tends to get all over and is caustic.

P.S. I've left a small jar of it sit on my workbench for about a year now, and it works just as well as it used to, and doesn't eat the plastic container it's in at all.

I Only used it once with X-wing minis, but for all my other stuff I like to use Pine Sol, or its generic counterpart often just called "pine cleaner" that comes in jugs twice the size for $2 less, making it $1 or so altogether. I would agree to an extent that you can get by without stripping these.

Do post anything you paint though!