The easy answer is, no. I've dissolved some damned stubborn absolutes in alcohol without heat, no problem. I think the most stubborn have been mimosa, benzoin resinoid, and various other literally solid bunches of what appears to be gunk. I have no experience with using oil, so I'll leave that one to those with more experience in that medium. Best advise I can give is to dilute the absolutes to 10% by weight or volume (weight being ideal, but not everyone has a scale at home). Most stuff dissolves fully in 24-48 hours so patience is a virtue. Additionally, not every absolute is pure. In my agarwood co2 and mate absolute, there are small layers of cloudy organic material that settle to the bottom of the bottle. I make no effort to filter, just carefully pipette off the top of the bottle and accept the loss of a little material in the interest of clarity of the final juice. I hope this helps. I have experimented with heating things, and invariably it requires a lot of attention I do not possess with a potential for dangerous spills of hot concretes and absolutes (my desk still smells of molten labdanum resinoid I made the mistake of turning my back on for 30 seconds).