Previous in vitro studies have demonstrated that aerosols from electronic cigarettes and indirectly heated tobacco products (HTPs) did not exhibit significant mutagenic or genotoxic effects, even at the highest exposure concentrations. To compare toxicity levels with that of cigarette smoke (CS) under low toxic concentrations, higher exposure of aerosol collected mass (ACM) from indirectly HTP is required. Conventional ACM extraction with organic solvents, like dimethyl sulfoxide (DMSO) induces solvent toxicity, complicating higher exposure. This study applies a solvent-free squeezing extraction method, to obtain concentrated ACM from indirectly HTPs (IT 3.0a). The solvent-free extract yielded approximately 10 times higher concentration than the DMSO extract, with similar extraction efficiency of main constituents. Ames test results indicated no mutagenicity up to 5000 μg/plate for both extracts. Similarly, micronucleus and neutral red uptake tests showed no additional genotoxicity or cytotoxicity at 5000 μg/mL. By contrast, the DMSO extract from reference CS exhibited significant toxicity at low concentrations. These findings confirm that the non-toxic dose for indirectly HTPs is approximately twice as high as previously reported, with a larger margin than observed in CS toxicity.