"An alcohol" could still apply, as the term "alcohol" in Chemistry terms includes a large amount of chemical compounds that exhibit similar traits (having oxygen bound to a hydrogen atom, hence OH), such as the most famous ethanol (also known as "white spirit"/ "pure alcohol"), methanol and more. Since it's a group, the plural of which happens to be "alcohols", they can have an indefinite article ("an") describing any single one.
I take it that your WMO is sticky too aye? I've tried white vinegar and that didn't work out, I got white spirit to try out next and then I'll try out a cleaning alcohol.