thats why you use heat and the gasket separator slugger tool. Most engine assemblies have a pry space or advise to use a sharp tool which is hammered into the joint of two assemblies - usually its the sheet metal oil pan.
This is the tool, you can make one too - or improvise on something like a stiff and sharp scraper. This tool is hammered into the flange surface and worked around a bit - which then lets go of the majority of the adhesive sealant.
For machined surfaces, find a pry surface or a hammering surface , All manufacturers provide that or have some holes where you can screw something in and use that to pull it apart. Like how you pull out a transmission oil pump. It has blind threaded holes for the job.
Now if you were using the now obsolete and oldschool caterpillar branded green gasket cement, I can assure you that you will have to employ violence of both kinds (fire and Thor's hammer) to get stuff apart and pre-order the part you are removing. I have actually lifted up entire engines from the unbolted valley and valve cover on some engines due to that green mess.
