Polishing is an Inventionperk that has a chance to transmute a gathered resource to a higher tier. It can be created in tool gizmos.
When the perk triggers, it prompts the message: Your polishing perk upgrades the gathered resource.
When Polishing activates, the experience gained in the gathering skill will be that of the original item, not the transmuted item. For example, if Polishing transmutes a regular log into an oak log, only 25 Woodcutting experience will be gained, instead of 37.5 experience.
Prior to a hotfix on 27 July2016, if polishing triggered on a sillago, it would upgrade it to a wobbegong and cause the fishing spot to instantly deplete - it was treated as if you fished the last wobbegong from a wobbegong spot, not like you caught a sillago from a sillago spot [1]
References[]
^Jagex. Mod Shauny's Twitter account. 16:56 27 July 2016. Mod Shauny: "#RSHotfix - Polishing will no longer upgrade fish to Wobbegong via fishing spots in the Arc. (This instantly depleted the spots before) ... Wobbegong fishing spots work differenly so when the perk upgraded it changed the spot hence why it instantly disappeared, there is no viable fix for this currently, but the Perk will work when catching a mid-tier > high-tier fish."