How can I remove window tint on the inside of a car?

The steamer option seems most promising if it will keep the adhesive with the tint film. Alternatively, you can rip the film off in seconds, leaving the adhesive behind. As an R&D engineer, I experimented with a variety of solvents from weak isopropyl alcohol to powerful acetone. The adhesive was most soluble in 91% isopropyl alcohol (70% rubbing alcohol might work well also). A spray bottle with the alcohol in one hand and a narrow plastic paint scraper in the other removes the adhesive quickly while the adhesive flecks dry rapidly and land on the floor. Avoid breathing vapors. Small areas or residues are easily scrubbed off with the alcohol on a rag followed by streak free window cleaner.