What to use to seal holes?

[RetroStang 13]

I have several tiny holes (1/8" to 1/4") in my trunk floor, under the rear seats, and other places. I'm planning to weld and patch these eventually, but probably not until next winter. Does anyone have any suggestion of a product I can use to seal them up, that is easily removable when I'm ready to patch them? I was thinking of putting some Dynamat over them, but I've heard that is difficult to remove. I keep seeing the ad on TV for that FlexSeal stuff, but haven't had any experience with it. Maybe a marine type sealer or a seam sealer?

[Caseyrhe 650]

I'd just fill them with silicone, can drill the spot out when patching. Anything else I would imiagine would be flamible and messy when patching

[JD08 42]

I used 3M Marine Adhesive on some pinholes that I plan to get back to someday but probably never will.

[Bob & Sue 110]

I had a Sea Ray 270 Sundancer the best sealer you can use is 3M 4000 Marine Sealer it's not hard to remove and won't leak or shrink and will hold up to heat and movement. Not to bad to remove just use a heat gun to warm it up first. I did four portlights ( windows ) on the boat five years ago with it it still looked like it was just done when we sold it last fall.

DO NOT GET THE 3M 5000 OR 5200 FROM HD YOU'LL NEVER BE ABLE TO REMOVE WITHOUT HOURS OF WORK.

https://www.amazon.com/3M-Hybrid-Adhesive-Sealant-Multiple/dp/B00VFIQNUC

[JayEstes 172]

You might consider using jb-weld.  This will actually come back out relatively easily by using a wire brush on a grinder.  You're going to weld them up anyway, so you'll need to grind them to bare metal anyway.  I'd just put a good piece of tape under the whole and mix up a small dob of JB-weld.  It will harden in the hole and the tape can be removed.  This idea will require the hole to be on a more or less flat surface - you would have to use something like "steel-stick" on a slanted or vertical surface.