Remove melted plastic from ceramic hob?

Plastic carrier bag left on hob which had a ring partially on. Melted plastic now stuck to it, got some off by scraping with a knife but don't want to scrape too much in case I score the ceramic. Have tried isopropyl and white spirit but neither helped. Any ideas anyone?
Kenny Cargill
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hob noun 1. a projection or shelf at the back or side of a fireplace, used for keeping food warm. 2. a rounded peg or pin used as a target in quoits and similar games. 3. a game in which such a peg is used. 4. Machinery. a milling cutter for gear and sprocket teeth, splines, threads, etc., having helically arranged teeth and fed across the work as the work is rotated.
quoits noun 1. quoits, (used with a singular verb) a game in which rings of rope or flattened metal are thrown at an upright peg, the object being to encircle it or come as close to it as possible. 2. a ring used in the game of quoits.
... who let him in, anyway ? :-) John T.
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wrote in message ---
Since some here obviously don't know what I'm talking about here's one: http://www.currys.co.uk/gbuk/household-appliances/cooking/hobs/belling-ch60t-ceramic-hob-granite-19347932-pdt.html?gclid=CjwKEAjw86e4BRCnzuWGlpjLoUcSJACaHG55vfMQmgvMWYD3VqizM2LTsBcP0ksZkQBUDhDukJsQSBoCQVfw_wcB&srcid 8&cmpid=ppc~gg~~~Exact&mctag=gg_goog_7904&s_kwcid=AL!3391!3!101175804444!!!g!64556378604!&ef_id=VwqXkwAAAPupgyhi:20160410181426:s
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Kenny wrote:

Heat up the plastic using a hair drier or similar. This should soften it and make the removal easier.
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On 4/10/2016 12:18 PM, Kenny wrote:

Plastic is probably polyethylene which is only soluble in hot hydrocarbon solvents. You might try hot mineral oil to avoid flammability hazard.
Melting point of polyethylene is somewhat above 100 deg. C so a heat gun might help to get off the bulk of it.
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On 4/10/2016 1:40 PM, Frank wrote:

Try putting ice on it to make it brittle and it may pop off.
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On 4/10/2016 1:57 PM, Ed Pawlowski wrote:

Usually dry ice is recommended for plastics. Water ice is not cold enough as glass transition temperature of PE is -78 deg. C.
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