If it is an air-tight closed from atmosphere incubator, just place inside one of the available CO2 absorbers, the simplest being 1 M KOH in the large beaker or plate or tub. Add filter paper to increase absorbing surface. Fan inside would be also helpful to remove all CO2 in 5-10 min. There are safer solid absorbers, e.g. a mixture of CaCl2:NaOH as well as more sophisticated commercially available absorbers. Could be other options, depending on what do you plan to do AFTER CO2 removal.