The different categories of samples and their treatments at the radiocarbon (14C) laboratory in Jena, Germany, are described. The Jena 14C laboratory is dedicated to studying the global carbon cycle through the analysis of soil, plant, gas, charcoal, and wood samples. The respective preparation procedures for different samples types are presented, including wet-chemistry pretreatments for soil decalcification, charcoal purification using an acid–base–oxidation procedure (ABOx), and α-cellulose extraction from wood and leaves. In particular, investigations of the background corrections for each sample type are emphasized. Furthermore, an investigation of the contamination resulting from the storage of graphite is presented. Four storage conditions are investigated for storage times up to 30 months.