What's the best material to use to seal the gap between my counters and the stove? It's a pretty tight fit but we don't want any crumbs and food bits to get in there.
If we use caulk will it stick to stainless? Will it leave a mark if we decide to remove the caulk?
There are metal and there are silicone rubber pieces with a T cross section designed for just for this purpose. https://www.amazon.com/Stovetop-Extender-SE24BLA-Oven-Guard/dp/B0027DW4QG. The tops of "slide-in" ranges cover the gap, but there is a gap when a "free-standing" range is used. These cover pieces work well for covering the gap. They keep anything from falling in, but allow cleaning under the cover strip. They also reduce heat transfer from the hot stove top to the counter top (compared to sealing the gap).
I use foam rubber weather stripping gaskets:
Alternatively, rubber hose works equally as well.
Just buy it in a profile slightly wider than the gap, then tuck it in the gap. Friction will hold it in place. And easy to replace if you ever need to pull the stove out.
Those gaps are rarely sealed because the stove needs to be moveable for cleaning and service. Food will get behind and under the stove, and you'll want to be able to pull it out and clean.
If you must do it, clear silicone (not a silicone blend) is typically the right product. It'll bond well to the countertop and the stainless (if properly cleaned), and it'll remove fairly cleanly when the time comes.
As isherwood noted, you don't want to do this in any permanent way. However, there are lots of companies that sell plastic/rubber strips that are meant to fit in this gap. Just Google strip to block gap between stove and counter and you'll find lots of fairly inexpensive options.
Google or search for "caulk backer rod". These are round foam strips for filling up gaps prior to caulking and I've seen them used to fill small gaps around kitchen appliances. You probably want the smallest one you can find for those gaps (well fitted BTW!). Gently push it in using a small, thin, flexible scraper until it's just out of sight.
Incidentally, it's also common to adjust the stove until it's level with the countertop, but it's personal preference, (or technical limitations) and won't affect the taste of your curry... ;-)
As mentioned above you shouldn't seal the gap as the cooker will almost certainly need to come out at some point and even a small silicone bead can hold like heck...
