The development of Coiled Tubing as we know it today dates back to the early 1960's, and it has become an integral component of many well service and workover applications. While the initial development of coiled tubing was spurred by the desire to work on live wellbores, speed and economy have emerged as key advantages for application of CT. In addition, the relatively small footprint and short rig-up time make CT even more attractive for drilling and workover applications. In addition, modern CT strings provide sufficient rigidity and strength to be pushed/pulled through highly deviated or horizontal wellbores. In April 2019, Exalo Drilling S.A. performed a job for PGNiG S.A. with cleanup of un-tubular section in one of the horizontal wells using a Coiled Tubing Unit equipped with a 1 ¾” CT pipe. That was a well with a final depth of 4800m MD (3583m TVD) and a horizontal section length of over 1000m, which is entirely located in the un-pipe section under the shoe of 7” pipes. Design works shown that the use of CT with 1 ¾” diameter in this case may prevent the achievement of the final depth. Due to such technical limitations, work began on the selection of appropriate technologies that would allow for the smooth implementation of this project. The first element to reduce the friction coefficient was the use of Friction Reducers for the fluid used during operation. This allowed both to reduce the frictional resistance at the contact between the CT and the walls of the extraction pipes in the well and significantly reduced the hydraulic resistance during the operation. An additional aspect to increase the possibilities of RIH to the bottom of the well in such a long horizontal section was the use of specialized downhole tools. In this case, the NOV Agitator™ was used, which significantly improved the possibilities when working in the horizontal section. This tool, causing the delicate vibrations of a set of downhole tools, reduces friction and significantly improves weight transfer and improves control over the front tool (milling cutter), reducing friction vibrations. This increased the possibilities associated with the reach, and prevented the coil from "getting stuck" in the hole. Properly selected technology for carrying out this job allowed for its smooth implementation using a CT string with 1 ¾” diameter.