Experts suggest that you toss your mascara every three months (guidelines here), but that doesn't always happen. Lots of us hang on to mascara longer than that, even when things get clumpy. Yesterday, geeksugar told me about her way to salvage the last bits of mascara.
Running hot water over a closed mascara tube often warms and liquefies clumpy mascara, but geeksugar had little success. Instead, she plugged the sink, let hot water fill it up, and tossed the tightly closed tube in there. A few minutes later, the mascara was — and I quote — "a fabulous, dreamy consistency." So there you have it.