Paint thinner and Mineral Spirits may NOT be the same thing. Be very careful if you are buying hardware store products for use with model paints and model plastic.
Testors thinner/brush cleaner IS essentially the same as Mineral Spirits (also called White Spirits). Some of the hardware stuff is "hotter" than others, but most should be just find for models. I have a bottle of Ace Hardware mineral spirits and that works fine.
But there are other paint thinner products on the market that are not mineral spirits... They can be for lacquers, etc. So be careful...
Enamels can be thinned with Mineral Spirits or Lacquer Thinner. For brush painting I use the MS... but for airbrushing, I always use LT. It makes them flow better, dry faster, etc. Good stuff!
Acrylics are generally thinned with water, or an acrylic thinner that looks, feels and smells suspiciously like Rubbing/Isopropyl Alcohol. I have thinned Testors, Poly Scale and Tamiya acrylics all with Water or Isop just fine.
However, you can thin many acrylics with Lacquer Thinner. It is a VERY good thinner for acrylics and I thin Tamiya paints wtih LT for airbrushing in particular.
If you want a universal thinner for both enamels and acrylics... try Lacquer Thinner.
Always test new thinners with different brands of paints just to make sure they work.