The investigation of light collection in plastic scintillators for gamma-ray detection is critical for enhancing their performance in high-energy physics, medical imaging, and radiation monitoring. This study systematically investigates the effects of optical grease and wrapping materials on light collection efficiency and the resulting light output. Two types of scintillators with contrasting transparency properties were tested: commercial scintillators with 68% transmittance and fabricated scintillators (PS1) with 2% transmittance. Results demonstrate that higher optical transparency significantly enhances light output. Silicone grease, as an optical coupling agent, moderately improved light collection efficiency, reducing losses by 21–36% compared to air coupling. Among wrapping materials, Teflon tape achieved the most efficient light collection, minimizing losses to as low as 10%, whereas aluminum foil tape resulted in losses of up to 53%. Additionally, the type of reflector wrapping impacted energy resolution. © 2026 Elsevier B.V.