What do you use to get out stuck bolts?

I've pretty much always used WD40 mainly because I always have it around and use it for other things besides rusty bolts.I've tried Liquid Wrench and PB Blaster and never saw much of a difference and the WD40 was cheaper than PB Blaster.I've been thinking about mixing some of the acetone/atf to see how that works because even WD40 is getting expensive.Sometimes it depends on what I'm doing and how fast I want to finish a repair,I usually won't waste a day waiting for penetrating oil to work if I don't have a very good reason to.I'll get out the fire wrench or if it's a through bolt,just snap it off and replace it with new,a bolt won't hold as well after it's been used and stretched a time or 2 anyway.If it's a bolt in a threaded hole,sometimes I'll wait on penetrating oil but I'm usually not afraid to cut the head off and get the drill out and drill it out if it doesn't look like penetrating oil is going to work.

Something else that I forgot to mention,I invested in a set of reverse twist drill bits a few years ago,these things are great for drilling out bolts.If your not familiar with them,you run the drill in reverse to drill the hole,usually between the heat built up while drilling and the vibration,once the bit bites just before it breaks through,it'll back the bolt right out of the hole.I do usually spray some penetrating oil in the hole as I'm drilling so that probably helps some also.

Penatrants only help SOME of the time IMO--and get costly ,at 4 bucks a can,that empties quickly..I'm going to use the ATF & Acetone mix,its certainly cheaper ,since I can get gallons of ATF free every time my friend does a tranny swap or fluid change at his shop..and fingernail polish remover can be had at the dollar store too,for a buck,while Acetone here is 12+ bucks a gallon!..

NOTHING beats an oxy-acetalyne torch though..I could fix nothing up here in saltland without one,and even WITH one,you cannot always get every bolt out..sometimes despite your best efforts and having all the right tools,skills,and patience,the bolts snap anyway..then your forced to drill them out and tap the hole (and DONT break off the TAP in the hole,OR the drill!)--and sometimes need to install a heli-coil..you become a machinist in a urry,whether you wanted too or not..I find broken bolts in blind holes very discouraging,especially in exhaust manifolds that now must be drilled out,while lying on the ground straight up over head..and all the chips go right in your eyes of course,etc..it's enough to make one suicidal,when you hear hat sickening "snap"..