How can I take linseed oil off wood that has dried sticky? It tried thinner, denatured alcohol, nothing works.
In addition to the good comments already made, I'll add that in order to remove cured drying oil, you will have to mechanically, not chemically, remove them. I am thinking a fine steel or brass wool, or maybe a scrubby pad, dampened with oil.
Unless it's unsightly though, I'd just leave it. It will slowly cure. It will never be hard, but it won't be gummy either.
I've used mineral spirits in the past to do this. Depending on how gummy things are (the earlier you do this, the better), you may need to scrub a bit, but given time it should come off.
In the future, you may want to dilute your linseed oil prior to applying - I find this makes things easier. (Personally I use linseed oil / polyurethane / mineral spirits in a 1:1:2 ratio, but you could leave the poly out and just go 1:1 linseed oil / mineral spirits for a similar result). The thinner solution helps you to not put it on too thick, and (may be anecdotal but it seems to work for me) helps to penetrate deeper into the wood.
I accidentally left some danish oil on a piece once (a hectic day/mind slip) over a weekend. I just applied some more oil to a cloth and gave it a good rub and it worked a charm. There was a lot of oil on the cloth when I was done which I used to oil a few small pieces I'd lying around that I'd never coated. Waste not want not and all that.