Regarding "making your own" and the "permanence" issue:
I also keep a supply of valve action pen-tip white-out correction pens from Staples, and clean out and refill these with thinned acrylics endlessly. Again, I have bodies that I have used for literally months on end, having run ounces of fluid through them.
I have also filled several of them with various solvents for doing spot corrections on my work... Zylene and lacquer thinner for oils, ammonia augmented Windex for acrylics, peroxide and laundry bleach for bleaching ink out, vinegar for neutralizing the bleach and one with baking soda solution for neutralizing the vinegar.
Well, You asked.