The menace of wastewater pollution in the 21st century is becoming alarming. Application of the low-cost adsorbents for wastewater treatment has received more attention this moment in environmental history than never. Therefore, remediating stale foundry wastewater with Activated Carbon, AC-250 is the focus of this study. Wastewater samples were collected from Lamina Foundry, Nitte, Karnataka State, India and were subjected to Atomic Absorption Spectrophotometry (AAS) analysis. The analysis identified the prominent heavy metals (Zn, Cu, Mg, and Pb) present in the stale foundry effluent, determined their respective concentrations and treated them using the commercially sourced activated charcoal, AC-250. Effects of four (4) factors viz: adsorbent dosage, contact time, stirring speed and pH on the adsorption process during the wastewater treatment were studied. Optimum conditions required for the most efficient treatment of the wastewater and the treatment cost estimates were determined. The AC-250 is found as efficient in adsorption of the heavy metals from foundry wastewater. In some of the cases a 100% removal is possible, especially with Pb. The analysis of the major experiments on effects of adsorbent dosage, contact time rotating speed and pH on the adsorption process, gave the optimum conditions for removal under which the most efficient treatment of the wastewater containing studied heavy metals was possible. For the optimum treatment conditions, an adsorbent dosage of 1 g, a contact time of 120 minutes, a rotating/agitation speed of 350 rpm and a pH value of 6 are established. An average cost of treating 1 litre of stale foundry wastewater is Rs 23 or 0.4 USD. This study therefore recommends AC-250 as an efficient adsorbent at the given optimum conditions for stale foundry wastewater. The reuse of AC-250 via the process of thermal reactivation at 8000C is encouraged as a means of waste management.