Use some kind of interchangeable cartridge in the exhaust line for fumes, bubbler as rhodium said for the KCN, as for ether how much are you venting?? if your using a fan to suck it out make damn sure its sparkless... If its simply removal of the solvent you could vent it out, vapours will rise and disperse....
Rhodium, couldnt one use a dryice cooled alcohol bubbler trap? then when wanting to remove the ether from it, add water? vent what ether doesnt dissolve?