Described herein are methods and materials for increasing the scavenging efficiency of hydrogen sulfide collected or produced in subterranean formations during wellbore environments. The methods can include first identifying a location that may include a concentration of production fluid that may contain high concentrations of H.sub.2S gas. The production fluid may be initially collected and tested to determine the concentration of H.sub.2S gas within the production fluid mixture. The production fluid, after testing, may then be treated, using in-line injection methods including a concentration of scavenging material to scavenge H.sub.2S gas from the production fluid and produce a cleaner gas after treatment.