I pass along this amusing advice, no doubt familiar to you, but probably not to the general HN readership.
"Gattermann (Ann. 357, 318 (1907)) recommends that the operator smoke during the preparation [of HCN], for he found that a trace of hydrogen cyanide is sufficient to give the tobacco smoke a highly characteristic flavor. This preliminary warning is useful in case of leaky apparatus or a faulty hood" - from Org Syn http://www.orgsyn.org/demo.aspx?prep=CV1P0314
"Gattermann (Ann. 357, 318 (1907)) recommends that the operator smoke during the preparation [of HCN], for he found that a trace of hydrogen cyanide is sufficient to give the tobacco smoke a highly characteristic flavor. This preliminary warning is useful in case of leaky apparatus or a faulty hood" - from Org Syn http://www.orgsyn.org/demo.aspx?prep=CV1P0314