Being honest, it is much safer to remove it all. The trouble is that the new silicone often softens the old stuff, bits break off and contaminate the new stuff causing a bad finish. I hate removing silicone so I feel your pain. The good news is that once you have most of it off like you have, I find that the rest comes of easy with a stainless pan scourer and a solvent cleaner or a nylon one if you have an unsteady hand and are worried about scratching. Something like this works good and it will be off in five minutes of scrubbing. https://www.toolstation.com/shop/Cleani ... ner/p31464
Other brands are available lol Silicone remover turns the surface to slush and I find that it's even worst to remove. Others may disagree. If you decide you can't face removing it then neutral cure silicone is less likely to dissolve the old or a hybrid polymer sealer like ct1 or stixall. Don't use the clear though it turns yellow after a while.
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