Widowsbane Paste

A cool, dark paste derived from the seeds of the bush of the same name, Widowsbane paste is an alchemical substance valued for its ability to dissolve spiderwebs. Something about the substance unravels web and negates its sticky properties, acting as both a lubricant for those trying to break free and a kind of fast-acting acid to any webbing it touches. 
Many homeowners pay for small amounts to speed up the removal of cobwebs, but in larger doses the substance can be a lifesaver against creatures like ettercap and giant spiders. Spraying a dose on one five-foot square requires an action, immediately destroying any non-magical webbing and allowing a character to move. Magical webs receive a contested check with the alchemist's level rolled against the level of the creature or magic-user who created the webbing.
Note that while a does of the paste removes a five foot square's webbing and frees characters trapped there, a character trapped in a larger area of webbing such as the Web spell still needs a method to bypass any other webbing in surrounding squares if they wish to escape the area entirely. Merely moving into an adjacent, webbed square forces the character to make the same save or roll they would have to make if entering the web for the first time.