I'm replacing some old silicon sealant around my bathroom sink. I've already done around the bath tub and that was fine: I removed the old sealant with a knife, cleaned it up and reapplied a new bead.

However, around the sink the old silicon (which has been there at least a few years) is very sticky, it's coming out as if it hasn't even cured, in sticky snotty globs. It's very hard to remove cleanly with a knife alone. Are there any methods for removing silicon that's in this state? Apart from the difficulties of getting it all out cleanly, is there anything else I should be concerned about? I'm wondering if some kind of chemical or process has led to the silicon being this way? I don't know what specifically was applied before or who applied it.

Here's a picture, I've got most of it out but it's really difficult to remove in the corner behind this tap.

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  • Hello, and welcome to Home Improvement. A picture of the (ick) silicone might be helpful. And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Jul 9 '19 at 13:49
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    Thanks. My guess is it's a "clean it all off, replace with quality caulk" situation, but let's see if anyone else has some suggestions. – Daniel Griscom Jul 9 '19 at 15:04
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    For cured silicone caulk use dimethyl adipate (often marketed as caulk remover) to soften it up; works amazingly well but only on silicone, it won't work on other caulking formulas. – Jimmy Fix-it Jul 10 '19 at 2:53
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    I've occasionally found silicone / silicone type formulas that are past their 'best before' date and refuse to cure. This might be that. (Ultimate irony is that the expiry date is usually unreadable... advice is to buy from somewhere with high turnover.) – Aloysius Defenestrate Jul 10 '19 at 13:23
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    It might not be silicone, it might be acrylic latex caulk like DAP or Polysemseal that was originally water based and may have gotten wet before it cured properly (people get impatient). people use latex caulk if they want paint to stick to it (paint will not stick to silicone). If so, you can aid removal by heating it up with a heat gun / paint stripper on a low setting, or a hair blow dryer on a high setting. – JRaef Jul 11 '19 at 2:15

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