Back then he could have configured it to search for Mersenne primes (https://en.wikipedia.org/wiki/Great_Internet_Mersenne_Prime_...) or the like. There's always been capacious sinks for computer power ^_^.

And I think the downvotes are uncalled for, the general idea is excellent, even if Bitcoin mining is iffy in a corporate setting (very bad if you keep them, and the finance people won't know what to do with them, plus their tax treatment is not trivial).

There are numerous way to heat a machine other then bitcoin mining( actually I doubt if bitcoins mining is the most efficient way)

He could, except this quote predates Bitcoin by at least five years. Oldest reference for this page in the wayback machine is in 2003. The quote may be even older than that.